LIBRARY 

OF  THE 

UNIVERSITY  OF  CALIFORNIA. 


BIOLOGY 

Class  LIBRARY, 

6 


LECTURES 


ON 


LOCALIZATION 


IN 


DISEASES  OF  THE  BRAIN 

DELIVERED  AT  THE  FACULTE  DE  MET>ECINE,  PARIS,  1875 


BY 


J.    M.    CHARCOT 


Professor  in  the  Faculty  of  Medicine  of  Paris  ;    Chief  of  the  Salpetriere  Hospital; 

Member  of  the  Acadhnie  de  Midecine  ;   of  the  Clinical  Society  of  London  ; 

President  of  the  Sociite  Anatomique  ;  former  Vice-President 

of  the  Societe  de  Biologie,  etc..  etc. 


EDITED 

BY 

BOURNEVILLE 

TRANSLATED    BY 

EDWARD  P.   FOWLER,  M.D. 


OF  THE 

UNIVERSITY 

OF 


NEW    YORK 

WILLIAM  WOOD  &  CO.,  27  GREAT  JONES  ST. 

1878 


.BIOLOGY 
RA 
G 


COPYRIGHT  BY 

WILLIAM    WOOD    &    CO., 
1878. 


TROW'S 

PRINTING  AND  BOOKBINDING  Co. 
205-213  East   \-ith   St., 

NEW   YORK. 


AUTHOR'S    PREFACE. 


THE  exposition  of  the  principles  underlying  the  doctrine 
of  cerebral  localization  seems  to  have  now  become  a  neces- 
sary chapter  of  introduction  to  the  practical  study  of  diseases 
of  the  brain. 

In  the  Lectures  which  Dr.  Fowler  has  kindly  taken  the  pains 
to  submit  to  the  appreciation  of  our  American  confreres,  I 
have  selected,  as  occasion  required,  information  furnished  by 
normal  anatomy,  experimental  physiology,  and  clinical  ob- 
servation, illustrated  by  minute  and  methodical  examination 
of  organic  lesions. 

I  have  always  given  precedence,  however,  to  the  last- 
mentioned  order  of  testimony,  convinced  that,  although 
normal  anatomy  and  experimental  physiology  may  serve  to 
indicate  the  true  direction  ;  still,  clinical  and  pathological 
research  is  necessary  (in  case  of  the  human  subject)  to  a  final 
judgment  and  to  the  furnishing  of  proof . 

I  shall  consider  it  as  a  great  honor  if  my  book  should  be 
favorably  received  in  a  country  where  instructors  in  neural 
pathology  are  represented  by  scientists  such  as  my  friend 
W.  Mitchell,  and  various  others  whom  I  might  enumerate. 


202754 


iv  AUTHOR'S   PREFACE. 

In  any  event,  I  cannot  sufficiently  thank  Dr.  Fowler  for 
the  care  which  he  has  bestowed  upon  the  translation,  and  I 
unhesitatingly  say  that  it  appears  to  me  a  model,  both  of 
scrupulous  exactitude  in  rendition  of  the  original  meaning, 
and  as  a  clear  and  unexceptionable  style  of  English. 

J.  M.  CHARCOT. 

PARIS,  Oct.  26,  1878. 


TRANSLATOR'S    PREFACE. 


No  excuse  is  required  for  contributions  to  medical  litera- 
ture which  are  calculated  to  increase  exactitude  of  expres- 
sion, ideas,  and  knowledge,  thereby  assisting  to  elevate 
medical  Art  to  the  higher  plane  of  Science. 

These  lectures  are  a  bold  example  of  that  cast,  as  in- 
deed are  all  of  Charcot's  teachings  and  writings. 

It  is  too  late  to  introduce  our  distinguished  author  to 
the  medical  profession,  for  wherever  medicine  is  taught 
as  a  science  his  works  are  already  known  and  prized,  and 
have  been  translated  into  nearly  every  modern  language. 
This,  however,  is  the  first  volume  which  has  been  pub 
lished  in  this  country. 

Charcot's  superstructures  are  always  built  with  great 
care  and  reserve  upon  the  secure  basis  of  induction,  though 
he  is  none  the  less  resplendent  in  the  rich  harvest  of  de- 
duction which  naturally  follows. 

The  translator  cannot  refrain  from  expressing  his  con- 
viction that  the  perfecting  of  medical  knowledge  depends 
mainly  upon  those  investigators  of  which  Charcot  is  so 
brilliant  and  so  sound  a  representative. 

NEW  YORK,  July,  1878. 


CONTENTS 


FIRST   LECTURE. 

PAGE 

Localization  in  Cerebral  Diseases . .  i 


SECOND    LECTURE. 
Structure  of  the  Gray  Substance  of  the  Brain 14 

THIRD    LECTURE. 

Considerations  upon  the  Normal  Structure  of  the  Gray  Substance 

of  the  Convolutions 24 

FOURTH   LECTURE. 
Parallel  between  Spinal  and  Cerebral  Lesions 33 

FIFTH   AND   SIXTH   LECTURES. 
Arterial  Circulation  in  the  Brain 41 

SEVENTH   LECTURE. 

Circulation  in  the  Central  Masses  (Gray  Ganglia  and  the  Internal 

Capsule) 59 

EIGHTH   AND  NINTH   LECTURES. 
Central  Arteries. — Isolated  Lesions  of  the  Gray  Ganglia 70 


viii  CONTENTS. 


TENTH   LECTURE. 

PAGE 

Cerebral  Hemianaesthesia  (Continued). — Crossed  Amblyopia. — Lat- 
eral Hemiopia 90 


ELEVENTH    LECTURE. 
Origin  of  the  Cerebral  Portion  of  the  Optic  Nerves 101 

TWELFTH   LECTURE. 
Secondary  Degeneration 115 


OF   THE 

UNIVERSITY 

OF 


LECTURES   UPON  LOCALIZATION 


IN 


DISEASES    OF    THE    BRAIN, 


FIRST  LECTURE. 

LOCALIZATION   IN    CEREBRAL  DISEASES. 

Summary  :—  Preamble.  —  Apparent  Aridity  of  the  Study  of  Cerebral 
Localization.  —  Principles  of  Localization. — The  Encephalon  in  a 
Morphological  Point  of  A' lew. — Necessity  of  an  Exact  Nomenclature. 
— Topography  of  the  Convolutions.  —  Importance  of  Comparative 
Anatomy. — Convolutions  of  the  Brain  of  the  Monkey;  Frontal,  Pari- 
etal, and  Sphenoidal  Lobes.— Psycho-motor  Centres.— Differences  in 
the  Composition  of  the  Gray  Substance  in  the  Various  Regions  of 
the  Brain. 

GENTLEMEN  : 

I.  We  will  devote  the  first  part  of  this  year's  course  to 
the  anatomico-pathological  study  of  the  encephalon.  Every 
one  in  an  audience  of  medical  practitioners  will  recognize  the 
importance  of  this  subject.  But,  with  some,  the  lack  of  an 
attractive  exterior  has  given  it  an  unfortunate  reputation.; 
in  this  particular  I  hope  to  inspire  you  with  a  different  sen- 
timent. Through  a  method  already  often  employed,  aided 
also  by  a  certain  amount  of  patience  and  perseverance — and 
that  will  not  be  lacking  on  my  part,  I  assure  you — I  think 
we  shall  accomplish  this  task  without  undue  fatigue  or  diffi- 
culty. 

To  avoid  leading  you  unprepared  into  the  domain  where 


2  DISEASES   OF  THE   BRAIN. 

we  shall  journey  together,  I  will  make,  by  way  of  an  intro- 
duction, some  observations  concerning  general  facts,  the  ap- 
plication of  which  facts  will  be  obvious  at  each  subsequent 
step. 

I  have  little  faith  in  the  value  of  generalities  when  unac- 
companied by  their  material  substructure,  and  especially  as 
concerns  pathological  anatomy.  I  will  therefore  supply  such 
groundwork  by  furnishing  a  certain  number  of  actual  illustra- 
tions. These  examples  will  be  taken  from  the  most  impor- 
tant chapter  in  encephalic  pathology,  that  treating  of  locali- 
zation in  cerebral  diseases. 

Various  reasons  have  decided  my  choice  of  subject.  In 
the  first  place,  it  is  one  of  those  fields  of  inquiry  where  the 
advantage  of  associating  clinical  with  anatomico-pathological 
studies  is  most  conspicuously  evident  ;  upon  the  principles  of 
cerebral  localization  is  founded  that  which  may  be  called 
regional  diagnosis  of  encephalic  diseases,  that  ideal  toward 
the  realization  of  which,  in  this  special  section  of  pathology, 
should  be  directed  all  the  efforts  of  clinical  teaching. 

Then,  again,  the  question  of  cerebral  localization  has  en- 
tered a  new  phase,  and  is  now  enlisting  world-wide  attention. 

We  should  not  make  undue  sacrifices  to  fashion,  but  on 
the  other  hand  we  must  not  undervalue  the  attractions  and 
the  new  facts  presented  by  recent  investigations. 

In  a  thesis  offered  at  the  last  conconrs  ^aggregation  de 
medecine,  this  interesting  chapter  has  been  handled  with 
great  ability  by  my  friend  and  old  pupil,  Dr.  Lepine,  agrege 
of  that  faculty.  I  shall  be  happy  to  utilize  the  delicately  dis- 
criminated observations  which  abound  in  that  work,  and  to 
turn  to  profit  the  wealth  of  erudition  which  the  author  has 
there  accumulated. 

It  is  understood,  of  course,  that  in  these  preliminary  lectures 
we  can  give  only  a  free  outline.  The  subjects  which  I  shall 
introduce  should  be  resumed  later,  submitted  to  a  more  pro- 
found study,  and  examined  in  their  most  minute  details. 

II. — Long  explanations  are  unnecessary  to  convey  what  is 
meant  by  localization  in  cerebral  physiology  and  pathology. 


LOCALIZATION   IN    CEREBRAL   DISEASES.  3 

The  term  has  long  since  become  a  common  one,  and  its 
meaning  is  well  known.  I  will  therefore  only  remind  you 
that  the  principles  of  cerebral  localization  rest  upon  the  fol- 
lowing proposition  :  The  encephalon  does  not  represent  an 
homogeneous  organ,  a  unit,  but  rather  an  association,  or  a 
confederation,  composed  of  a  certain  number  of  diverse 
organs.  To  each  of  these  organs  belong  distinct  physio- 
logical properties,  functions,  and  faculties.  Now,  the  physio- 
logical properties  of  each  one  of  these  parts  being  known,  it 
becomes  possible  to  deduce  therefrom  the  conditions  of  a 
pathological  state  ;  this  being  of  course  but  a  greater  or  less 
modification  of  the  normal  state,  and  not  a  result  of  the  inter- 
vention of  new  laws. 

We  will  employ  the  varied  knowledge  furnished  by  normal 
anatomy  and  experimental  physiology,  together  with  those 
clinical  observations  which  have  been  rendered  reliable  by  a 
methodical  and  minute  examination  of  organic  lesions,  and 
thus  endeavor  to  ascertain  upon  what  foundation  this  propo- 
sition rests.  The  importance  and  the  decisive  results  which 
depend  upon  these  last-named  examinations  cannot  be  over- 
stated. For  although  normal  anatomy  and  experimental 
physiology  may  often  suggest  the  true  direction  towards 
localization,  still  nothing  but  the  actual  examination  of  organic 
lesions  will  permit  a  final  decision  and  furnish  the  proof,  at 
least  so  far  as  concerns  the  special  subject  of  our  studies — man. 

A.  This  brings  us  to  an  examination  of  the  encephalon 
under  its  morphological  aspect.  It  is  understood  we  do  not 
attempt  a  rigorous  description  ;  I  propose  only  to  draw  a 
general  outline,  a  knowledge  of  which  is  indispensable  to  our 
object.  To  simplify  a  very  complex  situation,  I  will  confine 
myself  to  the  brain  ;  that  is,  to  that  mass  of  nervous  substance 
composed  of  two  hemispheres  and  situated  at  the  superior 
extremity  of  what  are  called  the  cerebral  peduncles  (crura 
cerebri). 

The  two  hemispheres  are  nearly  symmetrical,  and  so  nearly 
identical  in  their  structure  that  whatever  may  be  said  of  the 
one  may,  anatomically  speaking,  rigidly  apply  to  the  other. 
Each  one  is  enveloped  in  a  layer  of  gray  substance.  The 


DISEASES   OF  THE   BRAIN. 


central  part  is  formed  by  a  mass  of  white  substance,  in  which 
are  furrowed  the  ventricles,  and  where  are  also  seen,  as  if 
locked  together,  the  central  ganglionic  masses,  namely,  the 
thalami  optici  and  the  corpora  striata. 

A  transverse  section  made  to  intersect  the  corpora  mammil- 
laria  best  demonstrates  the  main  features  of  the  reciprocal 
relations  of  the  central  parts.  (Fig.  i.) 


Lenticular  ftud 

Horn  of  Anirnon 


Sphenoidal  Horn 
of  lat. Ventricle 


Post,  ceretral  Arteries 


FIG.  i. — Vertico-transverse  section  of  the  brain,  posterior  to  the  tubercula  mam- 
millaria  ;  anterior  to  the  peduncles. 

Immediately  above  the  protuberance  you  see  the  inferior 
face  of  the  crura  cerebri,  the  inferior  portions  of  which  issue 
mainly  from  the  anterior  bulbs  of  the  pyramids. 

From  the  lower  up  to  the  middle  part  of  the  section,  you 


LOCALIZATION   IN   CEREBRAL   DISEASES.  5 

will  see  two  large,  white  tracts  which  run  divergingly  towards 
the  cortical  portions  of  the  hemispheres.  They  are  between 
two  masses  of  gray  substance,  the  one  internal  and  superior, 
the  other  external  and  inferior.  These  two  tracts  are  the  pro- 
longations of  the  crura  cerebri  to  the  cerebral  hemispheres. 

The  crura  cerebri,  which  are  at  first  irregularly  quadrilateral, 
become  horizontally  flattened  as  they  enter  the  hemispheres, 
running  from  behind  forwards,  and  when  they  have  passed 
the  narrow  strait  of  the  ganglionic  region  they  open  and 
spread  in  every  direction — in  front  towards  the  frontal  ex- 
tremity, in  the  centre  towards  the  parietal  regions,  behind 
towards  the  occipital  extremity.  Burdach  calls  the  flattened 
interganglionic  parts  of  the  peduncles  the  internal  capsules  ; 
the  subsequent  expansion  has  been  called  by  Reil  the  cou- 
ronne  rayonnante,  diverging  fibres  ;  the  foot  of  the  diverg- 
ing fibres  is  where  the  peduncles  emerge  above  the  cerebral 
ganglia.  The  peduncles  as  they  enter  the  hemispheres  some- 
what resemble  a  spread  fan. 

Let  us  now  describe  briefly — returning  to  it  later — the  re- 
spective locations  of  the  cerebral  ganglia  in  regard  to  this  fan. 

When,  upon  making  the  classic  section,  the  lateral  ventri- 
cles were  opened,  you  will  remember  that  there  protruded 
upon  the  surface  two  masses  of  gray  substance  ;  the  anterior 
and  external  one  is  shaped  like  a  comma  or  a  glass  tear,  the 
large  extremity  or  head  of  which  is  anterior  and  the  small 
end  or  tail  (cue)  is  posterior  and  lateral,  and  is. called  the 
nucleus  caudatus  of  the  corpus  striatum  ;  the  other  mass  is 
internal  and  posterior,  and  is  ovoid — this  is  the  thalamus  opti- 
cus  ;  the  thalami  optici  arc  separated  by  the  base  of  the  third 
ventricle. 

These  two  intraventricular  gray  masses,  the  nucleus  cau- 
datus of  the  corpora  striata  and  the  thalami  optici,  rest 
above  and  within  the  peduncular  fan.  Below  the  fan,  and 
more  voluminous  than  the  other  two,  is  found  a  third  nucleus 
having  much  the  form  of  a  plano-convex  lentil,  from  whence 
the  name,  lenticulares  glandules  (Burdach).1  As  it  is  of 

1  In  French  nomenclature  it  is  called  the  extra  ventricular  nucleus  of  the 
corpus  striatum. 


6  DISEASES   OF  THE   BRAIN. 

equal  extent  antero-posteriorly  with  the  other  two,  it  will 
always  be  found  upon  transverse  sections  (frontal  sections  of 
the  Germans),  perpendicular  to  the  great  interhemispheric 
fissure,  whenever  the  others  are  met  with. 

The  study  of  transverse  sections,  made  at  methodical  inter- 
vals from  before  backward,  and  commenced  from  certain 
starting-points  upon  the  base  of  the  hemispheres,  is  indispen- 
sable to  a  familiarity  with  the  mutual  relations  of  the  ganglia, 
as  well  as  their  relations  to  the  peduncles,  and  it  is  also 
essential  to  the  clinicien,  whose  duty  is  to  precisely  deter- 
mine the  parts  diseased. 

I  will  describe,  as  our  studies  may  require,  the  appearance 
of  these  transverse  sections.  An  understanding  of  one  of 
the  most  posterior  of  these  sections,  made  immediately  in 
front  of  the  crura  cerebri  (Fig.  i),  is  all  that  we  need  at  the 
present  moment. 

You  here  see  the  flattened  portions  of  the  crura,  the  inter- 
nal capsules.  Within  these  are  seen  the  surfaces  of  the  thai- 
ami  optici  and  the  queues  of  the  corpora  striata.  To  the 
outer  side  of  the  internal  capsule  is  seen,  with  its  three  seg- 
ments, the  lenticular  nucleus  of  the  corpus  striatum.  These 
gray  nuclei  are  possibly  so  many  centres  endowed  with  dis- 
tinct properties  and  functions  ;  but  it  must  be  remembered 
that  this  is  not  yet  positively  demonstrated.  Still  external 
to  the  lenticular  bodies  you  will  discover,  in  succession,  the 
external .  capsules,  the  outer  walls  (little  white  unnamed 
bands),  and  lastly  the  gray  layers  of  the  island  of  Reil. 

I  have  no  intention  to  engage  at  present  with  details  of 
structure  ;  I  wish  only  to  insist  upon  these  designations 
given,  however  minute  they  may  seem  ;  for  years  past  I 
have  persisted  in  introducing  them  into  the  French  nomencla- 
ture only  because  I  have  considered  them  of  the  highest 
utility  when,  as  upon  autopsy,  it  is  desirable  to  indicate  the 
exact  locality  of  the  lesion.  Who  would  dare  to  affirm  that 
such  or  such  a  region,  which  has  no  place  in  our  nomencla- 
ture, is  not  possessed  of  an  importance  even  of  the  first 
order  ?  Besides,  how  can  such  region  be  described  in  a 
record  of  autopsy  if  it  has  no  recognized  name  ?  The  names 


LOCALIZATION   IN   CEREBRAL   DISEASES.  / 

which  I  supply  furnish  many  starting-points,  and  their  utility 
is  therefore  incontestable.  Is  a  good  strategic  chart  ever  too 
complete  ?  It  is  in  thus  precisely  specifying  the  spot  occu- 
pied by  a  hemorrhagic  centre — the  external  or  internal  cap- 
sules, the  gray  ganglia,  the  foot  of  the  diverging  fibres,  etc. — 
that  you  will  be  able  to  prove  whether  there  are  symptomatic 
differences  of  location  such  as  might  aid  prognosis.  An 
example,  presented  in  a  case  of  cerebral  haemorrhage,  will 
serve  as  proof  that  this  is  no  superfluous  labor.  If  a  haem- 
orrhagic  centre  involves  only  the  external  capsule,  what- 
ever be  the  extent  of  the  lesion,  the  patient  in  all  probability 
will  recover  without  persistence  of  hemiplegia  or  any  other 
infirmity  ;  but,  on  the  contrary,  if  it  be  the  internal  capsule 
that  is  involved,  and  the  patient  survives,  there  will  remain 
persistent  paralysis  and  permanent  contractions. 

The  importance  of  an  exact  and  minute  study  of  the  shape 
and  plan  of  the  brain,  joined  to  an  appropriate  nomenclature, 
is  especially  shown  when  dealing  with  the  convolutions  upon 
the  surface  of  hemispheres.  For  a  long  time  these  convolu- 
tions were  supposed  to  be,  as  it  were,  the  result  of  chance, 
and  thus  they  escaped  any  close  description.  Leuret  and 
Gratiolet  demonstrated  that,  on  the  contrary,  there  was  an 
orderly  plan,  which  could  be  traced  from  the  inferior  mam- 
malia, by  the  way  of  the  monkey,  up  to  man. 

Moreover,  there  are  among  the  convolutions  those  which 
can  be  called  fundamental,  for  the  reason  that  their  locations 
and  relations  are  absolutely  fixed  ;  then  again  there  are  those 
which  may  be  termed  secondary,  or  accessory,  and  which 
must  be  studied  abstractly,  because  they  are  variable. 

You  will  easily  comprehend  that  without  a  good  topog- 
raphy of  the  convolutions  it  is  quite  impossible  to  take  one 
step  in  the  more  important  knowledge  of  cerebral  localiza- 
tions. For  example,  how  can  we  speak  of  lesions  produc- 
ing aphasia  unless  we  are  able  to  determine  precisely  the 
location  and  form  of  the  third  frontal  convolution  ?  How 
could  we  locate  in  man  the  regions  called  psycho-motor, 
which  the  studies  of  Fritsch,  Hitzig,  and  Ferrier  have  discov- 
ered in  animals,  if  no  notice  be  taken  of  the  convolutions  and 


8  DISEASES   OF   THE  BRAIN. 

furrows  upon  the  gray  substance  of  the  parietal  lobes  and  the 
posterior  portions  of  the  frontal  lobes  ?  How  many  observa- 
tions which  might  have  thrown  light  upon  these  interesting 
questions  of  localization  are  valueless,  for  the  reason  that, 
from  an  insufficient  knowledge  of  the  altered  parts,  an  exact 
description  has  not  been  possible  !  In  order  to  obviate  as 
far  as  possible  that  lack  in  the  anatomical  description  of  the 
normal  brain,  I  have  for  a  long  time  past  habituated  myself 
to  outlining  the  locations  of  brain-lesions  upon  schemes  de- 
signed from  nature.  In  the  absence  of  these  precautions 
no  ideas  can  be  obtained  which  are  not  open  to  criticism. 
Still,  this  study  has  not  so  many  difficulties  as  may  at  first  be 
supposed.  If  the  most  complete  knowledge  has  not  yet  found 
its  way  into  classic  works,  it  nevertheless  abounds  elsewhere. 
Beyond  the  standard  works  of  Leuret  and  Gratiolet,  BishofT, 
Arnold,  Turner,  etc.  (a  familiarity  with  which  is  indispen- 
sable), I  recommend  to  your  use  the  little  manual  of  Ecker,1 
which  contains  good  topographical  plates,  accompanied  with 
a  simple  nomenclature,  together  with  synonyms.  Through 
my  advice  Duret  has  employed  these  plates  in  his  important 
memoire  upon  the  circulation  in  the  encephalon.  An  excel- 
lent work  upon  this  subject,  also,  is  a  thesis  by  Gromier,  written 
under  the  inspiration  of  Paul  Broca,  and  entitled,  "  Study 
upon  Cerebral  Convolutions  in  Man  and  Monkey.  1874." 

Comparative  anatomy  is  also  a  powerful  adjunct  in  the 
study  of  the  convolutions.  Between  the  monkey  and  man, 
for  example,  the  resemblance  is  striking,2  as  concerns  the  fun- 
damental convolutions  and  furrows,  and  that  arrangement, 
which  in  man  is  somewhat  unintelligible,  is  explained  in  the 
brain  of  the  monkey  by  reason  of  its  greater  simplicity.  I 
therefore  will  exhibit  a  sketch  of  the  convolutions  as  ob- 
served in  the  monkey  before  considering  those  of  the  human 

1  Die  Hirnwindnngen  des  Men  re  hen  nach  eigenen  Untersuchungcn  insbesondere 
iiber  die  Entwicklung  derselben  beim  Fotus  und  mit  Rucksicht  auf  das  BedUrf- 
niss  der  Arzte.  Brunswick,  1869.  There  is  an  English  translation  of  the  work. 

*  Upon  this  subject,  read  in  the  last  edition  of  Darwin's  "  The  Descent  of 
Man"  (London,  1874),  Professor  Huxley's  interesting  note  (p.  199),  on  the  resem- 
blances and  differences  in  the  structure  and  development  of  the  brain  in  man  and 
apes. 


LOCALIZATION   IN   CEREBRAL   DISEASES. 


brain.  This  study  possesses  additional  interest  from  the  fact 
that  actual  experiment  has  already  located  upon  some  of  the 
convolutions  of  the  monkey  brain  those  points  known  as  psycho- 
motor,  thus  furnishing  a  base  for  clinical  and  anatomico-patho- 
logical research  concerning  their  existence  in  corresponding 
points  of  the  human  brain. 

Here  is  a  lateral  representation  of  a  monkey's  brain  (Fig.  2) 


. 

IKoIor-cenlers  for  rotation. 
of  head&.neck 


Motor;  centers' 
movements 'of 
face 


1st- front.  con<v.    .Ascending  parietal  convr, 
2*  front.conv-.  \     w          r 

"ure  of  Rolando 

IMblor  centers  of  fore-legs 

d-obule'of  the  ascend  par.  Conv. 
/Lotor  centers  Or  kind-legs. 
Tor  cerlain  movements, 
of  eyes 'and  vision. 


Y- 
S'fnmt.cpmrn  I 

'   r  rotation,  j   I 
:ad  &.neckx^ 

Curvedfr 


Asc.fronl/-coar. 

Motor- centers  for  "hearing" 
moveinentSfof 


FIG.  2. — External  face  of  the  brain  of  the  magot  monkey  (Pithecus   Innuus). 
— Broca  and  Gromier. 

taken  from  the  work  of  Gromier.  It  is  a  brain  of  the  magot 
(Pithecus  innuus),  a  monkey  of  somewhat  low  type.  I  will 
give  a  description  of  the  external  face  of  the  hemisphere  only, 
the  internal  and  inferior  faces  being  of  less  importance  to  our 
subject. 

First,  two  long  fissures  are  seen,  the  fissure  of  Rolando 
and  that  of  Sylvius.  These  fissures  converge  and  constitute 
the  posterior  border  of  the  external  face  of  the  frontal  lobe. 

Further  back  is  seen  another  fissure,  the  parieto-occipital. 
In  the  monkey  this 'fissure  very  clearly  separates  the  occipital 
lobe  from  the  temporal  and  parietal  lobes.  This  separation 
is  much  less  marked  in  the  human  brain  on  account  of  the 
overlying  convolutions  (plis  de  passage)  which  more  or  less 
conceal  it. 


10  DISEASES    OF   THE   BRAIN. 

The  parietal  and  sphenoidal  lobes  are  less  distinguishable 
in  the  monkey,  and  to  complete  the  outline  it  is  necessary  to 
prolong  the  fissure  of  Sylvius  with  an  imaginary  line  passing  a 
convolution  called  the  gyrus  angular  is  (pli  courbe.) 

The  external  surface  of  the  cerebral  hemisphere  is  divided 
into  four  lobes,  the  frontal,  parietal,  sphenoidal,  and  occipital. 

Each  of  these  lobes  is  subdivided  by  fissures  or  sulci  of 
the  second  order  into  secondary  lobes,  called  convolutions. 

Frontal  Lobes. —  TJie  free  central  or  curved  frontal  fissure 
in  the  frontal  lobe  is  the  anterior  border  of  a  convolution 
lying  parallel  with  the  fissures  of  Sylvius  called  the  ascending 
frontal  convolution,  and  to  give  it  more  interest,  I  will  ob- 
serve that  in  its  superior  extremity  Ferrier  locates  the  motor 
centres  of  the  opposite  upper  limbs. 

Fissures  running  at  right  angles  with  the  curved  frontal 
fissure  divide  the  remainder  of  the  frontal  lobe  into  three 
convolutions.  1st  In  the  posterior  extremity  of  the  first  or 
upper  convolution  Ferrier  places  the  motor  centre  for  the 
movement  of  the  head  ;v  2d.  Upon  the  same  authority  the 
posterior  part  of  the  second  or  middle  convolution  is  the 
centre  of  facial  movements  ;  3d.  In  the  third  or  lower  convo- 
lution is  located,  in  the  monkey,  a  motor  centre  for  move- 
ments of  the  lips  and  tongue  ;  to  this  part  is  ascribed  in 
man  the  faculty  of  articulate  speech — the  third  convolution, 
or  as  the  English  call  it,  Brocas  convolution.  I  do  not  wish 
to  be  less  French  than  are  the  English,  and  in  adopting  the 
term  I  am  happy  to  recognize  the  signal  service  which  our 
colleague  has  rendered  to  the  cause  of  cerebral  localization. 

Parietal  Lobe. — The  parietal  lobe,  so  difficult  of  study  in 
man,  is  on  the  contrary  very  easy  in  the  monkey.  The 
interparietal  fissure  divides  it  into  two  secondary  lobes  :  1st. 
The  superior  parietal  lobe,  where  Ferrier  locates  the  centre 
for  movements  of  the  lower  limbs  ;  2d.  The  inferior  parietal 
lobe ;  3d.  A  fissure,  more  marked  in  the  higher  monkeys,  sepa- 
rates the  parietal  lobes  from  the  ascending  parietal  convolu- 
tion. In  a  part  of  the  ascending  parietal  convolution,  and 
extending  to  the  superior  extremity  of  the  ascending  frontal 
convolution,  is  the  motor  centre  of  the  upper  limbs. 


LOCALIZATION   IN   CEREBRAL   DISEASES. 


II 


Sphenoidal  Lobe. — The  situation  of  the  sphenoidal  lobe  is 
easily  understood.  Upon  the  convex  face  of  the  hemisphere 
it  is  bounded  by  the  lower  border  of  the  hemisphere  and  by 
the  fissure  of  Sylvius.  The  parallel  fissure,  called  thus 
because  it  is  parallel  to  the  fissure  of  Sylvius,  divides  the  lobe 
into  two  parts.  In  the  upper  part  is  found  the  marginal  con- 
volution, and  at  the  posterior  end  of  the  fissure,  the  gyrus 
angularis,  the  removal  of  which  Ferrier  says  produces  tem- 
porary blindness  of  the  opposite  eye. 

Occipital  Lobe. — A  transverse  furrow  separates  this  lobe 
into  two  parts.  For  the  present  there  is  nothing  special  to 
be  said  of  it. 

After  this  brief  survey  of  the  cerebral  convolutions  in  the 
monkey,  the  corresponding  ones  in  man  become  more  sim- 

Sup.  parifit'I  J/Me,  **•  &*>**<>*  /*  «,•  /  *y»y>. 
/  //**** 

, Of/Rolando,, 

-parietal  £ 
fissure^  *w 
PM 


s, 

a 


Fissure  of  Sylviu 


ParaEd'£ssure. 


FIG.  3. — Convex  surface  of  a  hemisphere  of  the  human  brain  (parietal  lobe  partly 
schematic.) 

plified,  as  proved  by  the  recapitulation  which  I  will  now 
give,  using  for  that  purpose  a  plate  from  Foville's  beautiful 
work  (Fig.  3). 

You  observe  that  the  fissure  of  Sylvius  and  the  fissure  of 
Rolando   furnish  the  inferior   and  posterior  borders  of  the 


12  DISEASES   OF   THE   BRAIN. 

frontal  lobe,  in  which  lobe  you  may  notice  the  ascending 
frontal  (or  anterior  parietal)  convolution  and  the  first,  second 
and  third  frontal  convolutions.  (Fig.  3.) 

The  parieto-occipital  fissure,  on  account  of  its  overlying 
folds  (pits  de  passage),  affords  but  a  confused  separation 
between  the  occipital,  parietal,  and  sphenoidal  lobes. 

Back  of  the  fissure  of  Rolando,  between  that  and  the  inter- 
parietal  fissure,  is  the  ascending  parietal  convolution  ;  above 
and  back  of  the  interparietal  fissure  you  will  find,  successively, 
the  superior  and  inferior  parietal  lobules  and  the  gyrus  angu- 
laris. 

In  the  sphenoidal  or  temporal  lobe,  the  brain,  both  of  the 
human  and  the  monkey,  has  a  fissure  that  extends  to  the 
gyrus  angularis  ;  this  is  the  parallel  fissure  ;  between  it  and 
the  fissure  of  Sylvius  lies  the  first  temporal  convolution  ; 
below  and  posterior  are  the  two  other  temporal  convolutions. 

The  parietal  lobe,  the  fissure  of  Sylvius  and  that  of  Rolando, 
afford  a  sufficient  number  of  starting-points  to  serve  as  guides 
in  autopsy. 

III. — Thus  the  surface  of  the  brain  is  marked  off  into  divi- 
sions, the  invariableness  of  which  cannot  be  misunderstood. 
Do  these  various  fundamental  convolutions  represent  distinct 
functional  centres  ?  A  consideration  of  only  the  external 
achitecture  cannot  resolve  the  question. 

We  will  now  resort  to  the  microscope  to  ascertain  whether 
a  comparative  study  of  structure  in  the  various  regions  of  the 
cortex  will  not  furnish  still  more  significant  information  upon 
this  subject. 

Unaided  vision  has  long  since  recognized  differences  of 
structure  in  the  gray  substance,  according  to  the  encephalic 
region  examined.  From  this  point  of  view  let  us  examine, 
for  example,  the  lower  portion  of  the  occipital  lobe.  In  those 
parts  of  the  lobe  which  surround  the  posterior  cornua  of  the 
lateral  ventricles,  the  gray  substance  is  not  of  that  almost 
uniform  appearance  which  belongs  to  other  regions  of  the 
brain,  as,  for  instance,  to  the  anterior  lobes.  Vicq  d'Azyr 
observed  that  in  those  parts  of  the  occipital  lobes  the  gray 


LOCALIZATION   IN   CEREBRAL  DISEASES.  13 

substance  of  the  convolutions  was  very  clearly  divided  into 
two  secondary  bands,  separated  by  a  white  line  which  is  still 
called  the  band  of  Vicq  cT Azyr.  In  this  respect  also  the  un- 
assisted eye  can  distinguish  between  the  gray  substance  of 
the  cornua  Ammonis,  the  isle  of  Reil,  and  that  of  other 
regions  of  the  hemispheres. 

To  appreciate   the  value  of  these  facts   it  is   necessary  to 
enter  more  into  detail. 


SECOND  LECTURE. 

STRUCTURE   OF    THE   GRAY    SUBSTANCE   OF    THE   BRAIN. 

Summary  : — General  Structural  Character  of  the  Brain-Cortex. — 1st ; 
Ganglionic  or  Nerve  Cells  ;  Pyramidal  Cells. — "Views  Respecting  the 
Nerve-Cells  of  the  Anterior  Cornua  of  the  Gray  Substance  of  the 
Spinal  Cord  (Motor-Cells);  Size,  Form,  Body,  Nucleus,  Niicleolus,  Pro- 
toplasma,  F  ibrillic  and  Granules ;  Nerve  Network  ;  Prolongations 
of  Protoplasma  ;  Nerve-Prolongations. — Comparison  of  the  Motor 
Nerve-Cells  of  the  Spinal  Cord  with  the  Pyramidal  Cells. — Pyram- 
idal Cells  ;  Size  ;  the  Small  Cells ;  the  Large  or  Giant  Cells  ;  Composi- 
tion of  the  Cells ;  Shape,  Body,  Nucleus,  Nucleolus  ;  Cellular  Prolonga- 
tions ;  Pyramidal  Prolongations;  Prolongations  which  Recall  those 
of  the  Protoplasma ;  Basal  Prolongations. — 3d  and  3d  ;  Elements  of 
Globular  Cells;  Elongated  Cells.— 4th  and  5th;  Medullary  Tubes; 
Neuroglia  or  Amorphous  Cerebral  Substance.— Relations  between 
the  Elements  ;  Five-layer  Type. — The  Importance  of  Examining  the 
Gray  Substance  of  each  Convolution. — Two  Divisions,  Structurally, 
of  the  Gray  Substance. — Labors  of  Betz. 

GENTLEMEN  : 

I.  The  structure  of  the  gray  substance,  in  whatever  region 
of  the  hemispheres,  presents  certain  general  characteristics 
which  should  be  examined  before  approaching  distinctive 
characteristics.  All  parts  of  the  cortex  are  composed  of 
essentially  the  same  elements.  Each  one  of  the  composing 
elements  may  present  important  relative  deviations  from  the 
standard  type,  according  to  the  region  observed  ;  and  in  a 
regional  study  of  the  gray  substance  great  weight  should  be 
given  to  the  different  proportion  and  manner  in  which  these 
elements  are  distributed  in  different  parts. 

After  having  examined  these  components  individually,  we 
will  investigate  as  to  how  they  combine  to  form  the  gray 
substance.  Our  description  will  commence  with  those  ele- 
ments which  play  the  principal  role,  that  is,  those  ganglionic 


THE   GRAY   SUBSTANCE   OF  THE   BRAIN.  15 

or  nerve-cells  which  are  the  special  characteristic  elements 
of  this  region  ;  they  are  usually  called  the  pyramidal  cells. 

In  order  to  fully  appreciate  the  morphological  properties 
of  these  elements,  perhaps  it  is  best  not  to  confine  our  atten- 
tion to  them  exclusively.  I  have  thought  best  to  employ  the 
comparative  method,  reposing  upon  the  common  saying  : 
"  Light  is  born  from  contrast"  ("  La  Imniere  nait  du  con- 
trast e  "). 

I  will  first  recite  the  principal  traits  of  that  nerve  cellular 
element  which  is  at  present  best  understood  :  I  refer  to  the 
nerve-cells  of  the  anterior  cormta  of  the  gray  siibstance  of  the 
spinal  cord,  called  the  motor  cells.  The  abridged  description 
which  I  will  give  of  these  nerve-cells  will  serve  as  a  type. 
In  the  comparisons  that  follow  I  shall  point  out  more  than 
one  difference,  but  I  shall  also  make  special  mention  of  more 
than  one  remarkable  analogy. 

The  motor  cells  are  cells  without  a  distinct  membrane,  the 
diameters  of  which  are  variable,  though  not  deviating  greatly 
from  0.050  m.  Gerlach,  however,  says  that  they  may  reach 
to  o.i  20  m.  Their  form  is  more  or  less  globular,  rarely 
elongated.  The  bodies  are  composed  of  protoplasm  which 
appears  granular  when  seen  in  the  non-living  state,  but  in  the 
serum,  or  after  the  action  of  osmic  acid  upon  the  fresh  cell, 
it  appears  to  be  composed  of  a  transparent  protoplasm  in  the 
interior  of  which,  as  Shultz  has  demonstrated,  exist  numer- 
ous fibrilla.  These  fibrillae  by  post-mortem  alterations 
change  to  granules.  The  cell  contains  a  nucleus  and  a 
brilliant  nucleolus.  I  also  generally  observe  in  the  proto- 
plasm, even  in  its  physiological  condition,  the  presence  of 
brown  pigmentary  granules. 

One  of  the  most  important  peculiarities  of  these  cells,  how- 
ever, is  that  they  are  armed  with  numerous  prolongations, 
which  have  a  voluminous  trunk  as  they  leave  the  cells,  and 
which  become  smaller  in  proportion  as  they  extend  and 
divide  (dichotomously).  The  last  of  these  ramifications  are 
extremely  minute,  and  it  is  difficult  to  trace  them  for  any 
distance. 

Gerlach,  after  the  use  of  preparations  of  chloride  of  gold, 


16  DISEASES    OF   THE   BRAIN. 

asserts  that  these  ramifications  terminate  in  a  sort  of  anas- 
tomosing network  which  he  called  reseau  nerveux.  These 
prolongations  are  composed,  like  the  cell-bodies  themselves, 
of  granular  protoplasm  and  long  parallel  filaments,  which 
may  be  traced  into  the  body  of  the  cells.  They  are  called 
protoplasmic  prolongations,  in  order  to  distinguish  them  from 
another  species  of  prolongation  which  I  will  now  describe. 

A  German  histologist,  Deiters,  some  years  ago  discovered 
an  important  fact  which  has  since  been  verified  by  all  anato- 
mists. It  is  that  the  greater  part,  if  not  all,  of  the  motor 
cells  possess,  besides  the  prolongation  which  we  have  de- 
scribed, a  prolongation  (one  only  for  each  cell)  which  charac- 
teristically differs  from  the  others.  These  prolongations  bear 
the  name  of  nerve-prolongations,  and  the  reason  of  that  quali- 
fication will  be  presently  understood.  It  proceeds  from  the 
body  of  the  cell,  or  from  one  of  its  larger  prolongations,  in 
the  form  of  a  very  slender  filament,  but  which,  little  by  little, 
becomes  more  voluminous.  This  prolongation  does  not 
ramify,  and  it  becomes  less  brightly  colored  by  action  of 
carmine  than  do  \h.t  protoplasmic  prolongations. 

If  followed  a  sufficient  distance,  it  is  found  to  be  enveloped, 
the  same  as  an  ordinary  nerve,  with  a  myeline  cylinder,  so 
that  it  may  be  considered  as  a  cylinder  axis  at  its  origin,  and 
at  a  certain  distance  as  a  complete  nerve.  The  connection 
of  the  nerve-cells  with  the  tubes  of  the  medullary  substance, 
by  means  of  these  prolongations  (nerves),  is  then  beyond 
doubt. 

Such  are  the  principal  characters  of  the  spinal  motor  nerve- 
cells  ;  and  here  seems  the  place  to  observe  the  characteristics 
of  the  pyramidal  cells  of  the  gray  cortex  (Fig.  4). 

These  cells  are  quite  variable  in  dimensions,  the  most  of 
them  are  relatively  very  small.  The  pyramidal  cells,  which 
may  be  placed  in  this  class,  have  at  the  base  a  mean  diameter 
of  o.oio  m.  Those  of  the  larger  sort,  less  in  number  than 
the  preceding,  generally  occupy  the  lower  portion  of  the 
layer  of  pyramidal  cells.  Their  diameter  attains  to  0.022  m. 
(Koschewnikoff). 

Finally   there   are   giant   pyramidal    cells    (Riesenzellen). 


THE  GRAY  SUBSTANCE  OF  THE  BRAIN. 


They  have  been  carefully  studied  by  Betz  (of  Kiew)  and  by 
Mierzejewski.  They  are  found  in  certain  well-determined 
regions  of  the  gray  cortex.  The  diameters  of  these  gigantic 
cells  sometimes  reach  0.040 
m.  to  0.050  m. ,  that  is,  they 
equal  the  cells  of  the  ante- 
rior cornua  of  the  spinal 
cord. 

However  they  may  differ 
in  dimensions,  the  essential 
structure  of  the  pyramidal 
cells  appears  always  the 
same.  Therefore,  for  con- 
venience' sake,  we  will 
study  the  larger  kind,  or 
the  giant-cells. 

To  a  certain  point  the 
term  pyramidal  cells  may 
be  used  literally  ;  their  form 
resembles,  indeed,  a  more 
or  less  elongated  pyramid. 
The  body  of  the  cell  re- 
calls the  description  which 
we  have  just  given,  and 
Schultz  records  that  he  has 
seen  fibre-like  structure  in 
it.  The  nucleus,  according 
to  very  many  authors,  is 
angular,  and  reproduces  in 
a  certain  degree  the  gen- 
eral form  of  the  cell.  The 
nucleolus  itself  presents  no- 
thing special. 

The  cellular  prolongations  offer  peculiarities  worthy  of  in- 
terest. One  of  them  may  be  called  pyramidal  prolongations, 
for  it  is,  as  it  were,  the  body  of  the  cell  progressively  nar- 
rowed. As  they  extend  they  give  off  lateral  branches,  and 
at  their  extremities  they  often  divide  in  form  of  a  fork,  and 
2 


FIG.  4. — Pyramidal  prolongation. 


1 8  DISEASES   OF  THE   BRAIN. 

this  extremity  is  always  directed  towards  the  surface  of  the 
convolution.  It  follows  that  the  cell  is  situated  so  that  its 
base  is  parallel  to  the  interior  or  medullary  border  of  the 
zone  of  the  gray  cortex. 

Other  prolongations  of  the  same  category  extend  some- 
times from  the  angles,  sometimes  from  the  base,  and  they 
ramify  in  such  manner  as  to  recall  the  protoplasmic  prolonga- 
tions of  the  spinal  motor  cells.  Do  these  prolongations  ter- 
minate in  a  nerve  network  in  the  gray  cortex,  the  same  as 
Gerlach  says  occurs  with  the  spinal  cells  ?  Some  authors  say 
they  do. 

There  certainly  exist  for  the  larger  pyramidal  cells,  for  the 
giant-cells,  and  perhaps  for  the  small  cells,  cylindrical  prolon- 
gations quite  analogous  to  those  of  the  spinal  motor  cells. 
In  both,  the  origin  is  a  slender  filament  which  soon  becomes 
somewhat  larger.  Upon  successful  dissections  it  is  possible, 
at  a  certain  distance  from  the  cell,  to  discover  that  the  pro- 
longations are  covered  with  a  cylinder  of  myeline.  Koschew- 
nikoff1  placed  this  fact  beyond  doubt  by  examination  of 
cells  from  the  anterior  lobes  of  the  brain  of  one  who  died 
from  encephalitis  ;  and  since  the  publication  of  his  work  the 
reality  of  his  description  has  often  been  demonstrated  by 
others.  These  basilar  prolongations,  to  use  Meynert's  expres- 
sion, are  always  turned  towards  the  medullary  substance  of 
the  convolutions. 

That  which  we  have  adduced  makes  it  impossible  to  misun- 
derstand the  analogies  associating  the  pyramidal  cells  of  the 
gray  cortex — at  least  the  large  cells  and  the  giant-cells — with 
the  motor  cells  of  the  anterior  cornua  of  the  spinal  cord  ;  and 
these  analogies  (already  described  by  Luys :  J.  Luys,  Recherche s 
sur  le  systeme  nervetix,  etc.,  p.  162  et  suiv.,  Paris,  1865)  we 
must  consider  later. 

1  A.  Koschewnikoff. — Axencylinderforsatz  der  Nervenzellen  im  kleinen  Him  des 
Kalbes.  In  Schultze's  Archiv,  p.  332,  1869.  Axencylinderforsatz  der  Nervenzel- 
len aus  der  Grosshirnrinde.  Idem,  1869,  p.  375.  Betz,  Centralblatt.  1874,  p.  579 ; 
Mierzejewski,  Etudes  sur  les  lesions  cerebrales  dans  la  paralysie  gen£rale,  in 
Archives  de  physiologic,  p.  194,  1875.  J.  Batty  Tuke,  Morisonian  Lectures,  in 
Edinb.  Med.  Journal,  p.  394,  May,  1874. 


THE  GRAY  SUBSTANCE  OF  THE  BRAIN.        IQ 

The  pyramidal  cells  are  not  the  only  elements  found  in  the 
gray  substance.  There  are  also  small  globular  cells  (rarely 
pyramidal),  measuring  from  0.008  m.  to  o.oio  m.  (Meynert),1 
sometimes  furnished  with  small  prolongations  ;  they  are 
generally  sparse,  though  sometimes,  or  at  some  points,  they 
form  a  tolerably  thick  layer.  Various  writers  have  regarded 
them  as  incompletely  developed  nerve-elements  ;  others  again 
have  denied  them  this  character,  and  compare  them  to  the 
elements  which  constitute  the  granular  layer  of  the  retina. 

Meynert  ranks  also  among  the  nerve-elements  of  the  corti- 
cal zones  a  kind  of  elongated,  generally  fusiform,  ramified 
cell,  and  which  at  certain  points  constitutes  a  fifth  layer. 
These  cells  generally  have  their  grand  axis  directed  parallel 
with  the  fibres  which  connect  the  convolutions  (the  system 
of  association},  medullary  fibres  that  run  from  one  convolution 
to  another  (fibrae  arcuatse)  ;  the  last-named  cells  seem  to 
make  a  part  of  that  system. 

These,  then,  are  the  cellular  nerve-elements,  so  reputed, 
which  enter  into  the  structure  of  the  gray  substance.  Besides 
these,  there  are  other  elements  which  we  ought  to  mention  : 
the  medullary  tubes  and  the  amorphous  cerebral  substance 
(neuroglia).  To  these  last,  which  penetrate  the  gray  substance 
as  fasciculi,  we  will  return  later.  As  for  the  neuroglia,  still 
known  under  the  name  of  formation  ependymaire  (Roki- 
tansky),  that  serves  as  an  amorphous  uniting  substance.  I 
will  not  enter  into  the  detail  of  the  peculiarities  of  structure 
relative  to  the  neuroglia  of  the  gray  substance.  I  will  only 
remark  that  latterly  it  has  been  considered  by  various  authors 
as  composed  of  a  peculiar  kind  of  conjunctive  cells,  the  bodies 
of  which  contain  very  little  protoplasm,  and  are  furnished 
with  non-ramified  prolongations  (cellules  araignees  de  Boll  et 
Golgi).  These  prolongations,  entangled  and  cemented  by  an 
interposed  gelatinous  substance,  would  be  considered  as  com- 
posing the  entire  mass  of  neuroglia.  We  must  examine  that 
interpretation.  Without  denying  the  normal  existence,  in 
certain  regions,  of  ramifying  cells  (cellules  de  Deiters),  I  will 

1  Meynert.— Strieker's  Handb.,  t.  II.,  et  traduct.  anglaise,|t.  II.,  p.  381  et  suiv. 


2O  DISEASES   OF  THE   BRAIN. 

remark  that  the  gray  substance  in  that  respect  is  very  likely 
fashioned  upon  the  same  model  as  is  the  white.  In  other 
words,  the  neuroglia  resembles  the  type  of  ordinary  conjunc- 
tive tissue,  conjunctive  fasciculi,  and  flat  cells  (Ranvier)  ;  only 
in  the  neuroglia  the  fibrous  filaments  would  be  freer  than  else- 
where. For  the  present,  I  omit  the  study  of  the  vessels  ;  they 
will  shortly  receive  our  special  attention. 

This  suffices,  I  think,  concerning  the  individual  history  of 
the  various  elements  which  compose  the  gray  substance. 
We  should  now  examine  the  method  in  which  these  elements 
are  arranged,  in  order  to  see  what  may  be  the  difference  in 
arrangement,  as  well  also  as  in  respect  to  the  constitution  of 
the  elements  themselves,  in  each  of  the  various  regions  which 
are  divided  off  by  the  main  fissures  on  the  surface  of  the  brain. 

There  is  a  certain  arrangement  which  may  be  considered 
as  representing  the  most  common  type,  and  it  is  also  the 
most  widely  extended  ;  it  is  the  one  that  in  thin  slices  may 
be  distinguished  with  the  microscope,  and  which  presents 
five  successive  layers.  It  is  met  with  nearly  everywhere  in 
the  anterior  lobes.  The  elements  are  separated  as  follows  : 

i.  The  first  layer,  the  one  nearest  the  meninges,  is  com- 
posed almost  exclusively  of  conjunctive  substance.  There 
the  nerve-elements  are  very  scarce  ;  Kolliker  and  Arndt,1 
however,  describe  a  layer  near  the  surface,  under  the  pia 
mater,  of  very  delicate  parallel  nerve-tubes.  The  nerve-cells 
in  this  locality  are  very  sparse.  To  the  naked  eye  that  layer 
has  the  appearance  of  a  little  white  zone.  The  absence  of 
color  seems  due  to  the  poverty  of  nerve-elements  and  to  the 
small  number  of  capillary  vessels  contained  in  the  layer. 
Indeed  the  arterioles  penetrating  the  cortex  do  not  furnish 
numerous  capillaries  except  to  the  lower  layer.  That  pecu- 
liarity of  structure  is  very  well  indicated  in  a  plate  by  Henle,2 
and  in  a  cut  in  the  memoire  of  Duret.3 

1  R.  Arndt. — Studien  iiber  die  Architektonick  der  Grosshirnrinde  des  Menschen, 
in  Arch,  fur  mikroskop.  Anatomic,  3d  Bd. — 1867,  p.  441,  Taf.  xxiii.,  Fig.  i,  a,  et 
Fig.  2. 

2  J.  Henle. — Handb.  der  Nervenlehre,  p.  274,  Fig.  201,  Braunschweig,  1871. 

3  Archives  de  Physiologic,  T.  vi.,  pi.  6,  Figs.  2  et  3. 


THE  GRAY  SUBSTANCE  OF  THE  BRAIN. 


21 


2.  The  second  layer  (Fig. 
5)  is  marked  by  an  agglom- 
eration of  pyramidal  nerve- 
cells  of  the  small  species, 
numerous    and    very   close 
together,    which   give    it  a 
decided  gray  color. 

3.  The  third  layer  (Fig. 
5)    is  chiefly  composed  of 
pyramidal     cells,    some    of 
the  medium  size  and  some 
voluminous.       The    latter, 
more  separated   from  each 
other    than    the    first,    are 
generally   situated    at    the 
lower  part  of  the  layer,  and 
penetrate    even     into    the 
next  (fourth)    layer.       Be- 
sides the  cells  there  are  to 
be  found  in  the  third  layer 
fasciculi  of  medullary  fibres 
which  dip    perpendicularly 
to  the   surface   of  the   cor- 
tex, forming  as  it  were  col- 
umns between  the   groups 
of  pyramidal  cells.   This  ar- 
rangement has  been  faith- 
fully represented  by  Luys  l 
and  by  Henle.2    It  is  in  the 
lower  portions  of  the  third 
layer  that  in  some  regions 
the   giant-cells     exist.      It 
would  seem  as  though  the 
rarity  of  cells  and  the  pres-   ~ 
ence    of    medullary   fibres 
ought  to  give  this  layer  a 

white  appearance  ;    it  really       FIG.  5.— Five-layer  type  of  cerebral  cor- 
i  11-1  i       tex.          (Brain     of    mamrr 

has  a  yellowish  COlor,  prob-   prom  Strieker's  Hand-book. 


mammalia.)  —  Meynert. 
T.  II.,  p.  704. 


1  Atlas,  etc.,  pi.  xx.,  Fig.  4. 


2  Loc.  cit.,  Fig.  198,  p.  271. 


22  DISEASES   OF  THE   BRAIN. 

ably  from  the   presence  of  pigment  and   the   abundance   of 
capillary  vessels. 

4.  Then  comes  the  fourth  layer  (Fig.  5),  where  are  seen  the 
globular  cells  with  ill-determined  characters,  and  the  fifth 
layer,  where  are  found  the  fusiform  cells  of  which  we  have 
just  spoken. 

These  summary  investigations  have  enabled  us  to  appre- 
ciate the  interest  which  might  result  from  an  examination  of 
the  structure  of  the  gray  cortical  substance,  made  convolu- 
tion by  convolution.  It  has  long  been  known  that  the  differ- 
ent regions  of  the  gray  cortex  differ  notably  from  each  other 
in  point  of  structure.  But  the  most  recent  and  fertile  study 
in  this  direction  is  by  Betz,  the  results  of  which  have  been  pub- 
lished in  the  Centralblatt  of  the  past  year.1  Betz  proposes 
examining  the  modifications  of  texture  of  the  gray  substance, 
convolution  by  convolution.  In  this  respect  he  claims  that 
on  the  surfaces  of  the  hemispheres  there  are  two  fundamental 
regions  which  are  nearly  divided  by  the  fissure  of  Rolando. 

Anterior  to  that  furrow  the  gray  cortex  is  characterized  by 
a  predominance  of  large  pyramidal  cells  over  the  globular 
cells.  The  orbital  region  is  included  in  this  division. 

Back  of  the  furrow  this  region  embraces  all  the  sphenoidal 
and  occipital  lobes  and  the  median  portion,  to  the  anterior 
border  of  the  quadrilateral  lobule.  There  the  granular  cells 
preponderate,  and  the  large  ones  are  relatively  rare. 

Besides  this  there  is  a  special  department  in  each  of  these 
regions  which  deserves  attention.  We  will  deal  first  with  that 
of  the  posterior  region. 

ist.  Here,  the  well-developed  nerve-elements  are  the  toler- 
ably large  cells.  According  to  Meynert  they  were  the 
largest  found  in  the  cortex  of  the  hemispheres  before  the  dis- 
covery of  the  giant-cells.  They  are  sometimes  the  0.030  m. 
in  diameter.  The  protoplasmic  prolongations  are  not  nu- 
merous ;  the  basilar  prolongations  are  directed  horizontally, 
and  sometimes  constitute  communications  between  the  cells. 

1  P.  Betz,  of  Kiew. — Anatomischer  Nachweis  Zweier  Gehirncentra.  In  Cen- 
tralblatt, 1874,  Nos.  37  et  38. 


THE  GRAY  SUBSTANCE  OF  THE  BRAIN.        23 

The  territory  where  that  character  is  observed  includes  (a) 
the  cuneus ;  (b)  the  posterior  half  of  the  lingual  and  fusiform 
lobules  ;  (c)  all  the  occipital  lobe  ;  (d)  the  first  two  sphenoi- 
dal  convolutions  and  the  transition  convolution  (pit  de  pas- 
sage]. According  to  Betz,  this  region  is  devoted  to  the 
functions  of  sensibility.  From  other  reasons  of  an  anatomi- 
cal order,  to  which  we  will  revert,  the  posterior  parts  of  the 
brain  have  for  a  long  time  past  been  spoken  of  as  the  seat  of 
the  sensorium. 

2d.  The  anterior  lobe  deserves  particular  notice,  and  may 
be  called  (you  will  see  why)  the  department  of  the  giant 
pyramidal  cells,  or  the  motor  cells  par  excellence.  This  de- 
partment embraces  the  entire  ascending  frontal  convolution, 
the  superior  extremity  of  the  ascending  parietal  convolution, 
together  with  a  part  which  we  will  soon  study  under  the 
name  of  paracentral  lobule,  and  which  is  situated  upon  the 
internal  face  of  the  hemisphere  at  the  extremity  of  the  as- 
cending convolutions.  It  is  here  that  exist  almost  exclusively 
the  giant-cells.  Their  distribution  is  not  uniform,  for  they 
are  more  numerous  than  elsewhere  at  the  superior  extremity 
of  the  two  middle  convolutions,  and  above  ttll  in  the  para- 
central  lobule.  They  are  located  in  groups  or  islands. 
They  are  to  be  found  in  certain  points,  which  will  be  indi- 
cated, in  all  species  of  monkeys,  the  inferior  as  well  as  the 
chimpanzee.  Indeed  Betz  has  observed  in  the  dog  the 
same  kind  of  cells  at  those  points  designated  by  Fritsch  and 
Hitzig  as  motor  centres — otherwise  spoken  of  as  the  parts 
neighboring  the  sulcus  cruciatus.  Interest  is  added  by  the 
fact  that  in  the  dog  the  giant  pyramidal  cells  exist  nowhere 
else  but  in  the  regions  called  psycho-motor.  It  doubtless  has 
not  escaped  your  notice  that  in  the  monkey  the  distribution 
of  the  large  nerve-cells  very  closely  corresponds  to  those  con- 
volutions where  experiments,  in  the  hands  of  Ferrier,  have 
demonstrated  the  existence  of  motor  points,  namely,  in  the 
central  convolutions.  This  is  an  interesting  result  furnished 
by  histological  study,  and  which,  combined  with  experimental 
or  anatomico-pathological  results,  cannot  fail  to  throw  some 
light  upon  the  development  of  cerebral  localizations. 


THIRD   LECTURE. 

CONSIDERATIONS    UPON    THE    NORMAL    STRUCTURE    OF 
THE  GRAY  SUBSTANCE  OF  THE  CONVOLUTIONS. 

(CONTINUATION.) 

Summary :— Description  of  a  Section  of  the  Gray  Matter  of  the  Cere- 
helium. — Type  of  the  Five-Layer  Stratifications  of  Cellular  Nerve- 
Elements.— Regions  where  this  Type  of  Stratification  Exists.—  De- 
partment of  Pyramidal  or  Giant-Cells.— Relations  between  the  Cells 
and  the  Psycho-motor  Centres. — Description  of  the  Internal  Face  of 
the  Cerebral  Hemispheres. — Paracentral  Lobule. — Ascending  Convo- 
lutions.—Clinical  and  Experimental  Facts  Relative  to  the  Develop- 
ment of  the  Pyramidal  Giant-Cells.— Structure  of  the  Gray  Matter 
in  the  Posterior  Regions  of  the  Encephalon. 

GENTLEMEN  : 

Before  proceeding  further  towards  the  purpose  of  our 
subject — the  theory  of  localization  in  cerebral  maladies — 
I  ought  to  complete  the  matter  broached  in  the  last  lecture, 
relative  to  the  differences  in  the  normal  structure  of  the  gray 
matter,  as  found  in  the  various  convolutions  of  the  cerebral 
hemispheres. 

A.  We  will  first  examine  the  common  type,  or  the  one  most 
generally  and  best  understood.  With  Meynert,  one  may  call 
it  the  five- layer  type  of  cellular  nerve-elements — so  reputed. 

I  will  briefly  recall  the  characteristic  traits  of  that  type. 
To  assist  in  this  let  us  again  glance  at  Fig.  5,  a  section  of  the 
third  frontal  convolution  at  the  base  of  a  fissure. 

As  a  contrast,  we  will  run  over  the  description  of  a  section 
of  the  gray  substance  of  the  cerebellum  ;  this  description,  like 
the  preceding  one,  is  borrowed  from  Meynert.  In  the 
gray  substance  of  the  cerebellum  there  are,  in  successive 
order  :  1st.  A  thick  layer,  poor  in  cellular  elements,  and 
which  receives  the  protoplasmic  prolongations  from  the  nerve- 


NORMAL   STRUCTURE   OF   THE   CONVOLUTIONS.  2$ 

cells  of  the  subjacent  layer.  2d.  Below  this,  a  layer  where 
are  found,  according  to  Meynert,  fusiform  cells  and  medul- 
lary fibres  running  parallel  to  the  line  of  limit.  3d.  Still 
lower,  the  cells  of  Purkinje,  which  occupy  the  superior  por- 
tion of  a  very  granular  layer  ;  below  all,  the  medullary  sub- 
stance.1 

If  you  now  examine  the  figure  representing  the  five  layers 
of  gray  substance  of  the  brain  proper  (cerebrum),  you  will 
see  that  the  gray  substance  is  not  fashioned  in  all  parts  of 
the  encephalon  upon  the  same  model.  I  shall  shortly  show 
you  the  very  well-defined  though  not  so  strongly  marked  dif- 
ferences that  are  apparent  according  to  the  different  regions 
examined  in  the  cerebrum  ;  but  first  I  must  return  to  the  five- 
layer  type. 

B.  The  arrangement  thus  designated  exists  in  all  the  brain 
anterior  to  the  fissure  of  Rolando,  as  well  also  as  a  little  back 
of  it,  in  a  portion  of  the  parietal  lobes  which  is  indistinctly 
separated  from  the  border  of  the  occipital  lobe.  We  will 
presently  see  that  this  type  is  notably  modified  in  the  pos- 
terior part  of  the  encephalon,  including,  1st.  All  the  sphe- 
noidal  lobe  ;  2d.  The  occipital  lobe  ;  and  3d.  The  gray  matter 
of  that  portion  of  the  internal  face  which  is  circumscribed  by 
the  posterior  extremity  of  the  occipital  lobe  and  by  a  furrow 
which  is  the  posterior  limit  of  a  distinct  region,  which  we  will 
shortly  describe  under  the  name  of  the  quadrilateral  lobule. 

(a.)  For  greater  clearness  it  is  necessary  to  revisit  a  point 
already  surveyed  ;  namely,  that  in  those  regions  of  the  hemi- 
spheres occupied  exclusively  by  the  five-layer  type,  there 
exists  a  department  of  itself,  where  the  gray  structure  is  dis- 
tinguished by  an  interesting  peculiarity  ;  which  is,  the  invaria- 
ble presence  in  those  parts  of  comparatively  enormous  pyram- 
idal cells,  and  which,  on  account  of  their  size,  are  called  giant- 
cells.  While  these  cells  retain  the  pyramidal  form  common 
to  the  cellular  nerve-elements  of  these  regions,  they  differ 
not  only  in  dimensions,  but  also  by  the  distinctness  of  their 
nerve-prolongations  and  by  the  development  of  their  proto- 

1  Voir  aussi  Henle,  Nervenlehre,  etc.,  Figs.  162,  163  A,  163  B. 


26 


DISEASES    OF  THE   BRAIN. 


plasmic  prolongations.  This  last  trait  permits  their  compari- 
son with  the  motor  nerve-cells  of  the  anterior  cornua  of  the 
spinal  cord. 

The  regions  of  this  important  peculiarity  are  the  central 
regions  of  the  external  surface  of  the  hemisphere,  to  wit  : 
the  ascending  frontal  convolution,  the  ascending  parietal  con- 
volution, especially  at  their  superior  parts,  and  finally  in  a 
little  lobule  situated  upon  the  internal  face  of  the  hemisphere, 
until  recently  unnamed,  and  which  Betz  has  proposed  to  call 
\hzparacentral  lobule,  (Fig.  6.) 

Sujx  extremity  of  fisS.  of  Rolando, 
Iransverse  furrow  of  paracentral  lobiLlc.'' 

Tril. face' of  fir-si 
•frontal  convolution. 


FIG.  6. 

nature.")  * 


ge.  or.  Cuneiform  lobule.-' 

j  Occipital  lobe.  * 

AnrJLexLT>ortmofCrus  Ceretri        'Cavity  of  .lateral  veritncle- 
Cioioid  plexus. 

Internal  surface  of  right  hemisphere  of  a  human  brain.    {Drawn  from 


I  would  remind  you  that  the  existence  of  the  giant-cells  in 
the  gray  matter,  and  their  localization  in  the  regions  above 
indicated,  were  discovered  by  Betz  and  Mierzejewski.  The 
results  obtained  by  these  authors  have  recently  been  con- 


1  Respecting  the   topography  of  the  median  face  of  the  cerebrum,  consult  pi. 
viii.  of  Foville's  Atlas,  and  Fig.  4  of  Ecker's  work. 


NORMAL   STRUCTURE   OF  THE   CONVOLUTIONS.  2/ 

firmed  by  J.  Batty  Tuke  in  his  lectures  at  Edinburgh.1  I 
have  myself  also  verified  the  same. 

I  again  remind  you  that  the  regions  remarkable  for  this 
peculiarity  of  structure  are  precisely  those  where,  in  the 
monkey,  according  to  Ferrier,2  the  psycho-motor  centres  of 
the  limbs  are  located.  Is  not  that  a  coincidence  worthy  of 
your  attention  ?  Let  us  recall  the  fact  also  that,  in  the  dog, 
those  parts  reputed,  through  the  experiments  of  Ferrier  and 
by  the  previous  ones  of  Hitzig,  as  excito-motor,  are  said  by 
Betz  to  be  distinguished  by  the  presence  of  giant  pyramidal 
cells — cells  which  in  these  animals  are  to  be  found  in  no  other 
part  of  the  gray  matter.  I  think  my  persistence  justified  by 
the  necessity  of  fixing  in  your  minds  as  exactly  as  possible  all 
these  details. 

(<£.)  These  facts  give  a  very  special  interest  to  those  regions 
of  the  hemispheres  which  possess  this  anatomical  peculiarity. 
I  therefore  feel  that  a  thorough  topographic  knowledge  of 
those  regions  is  of  the  utmost  use  in  order  to  be  able  to  indi- 
cate them  with  precision  in  the  records  of  autopsies,  and  con- 
sequently I  will  enter  this  subject  more  fully.  In  so  doing 
we  shall  of  course  have  occasion  to  describe  the  configuration 
of  the  middle  faces  of  the  hemispheres,  a  region  which  up 
to  the  present  time,  in  my  opinion,  has  remained  too  little 
known. 

The  arrangement  of  the  ascending  convolutions,  their  ori- 
gin at  the  superior  border  of  the  hemispheres,  are  now  so 
familiar  to  us  that  our  attention  can  be  turned  to  the  arrange- 
ment of  the  internal  or  median  faces  of  the  hemispheres.  In 
that  section  (Fig.  6)  which  divides  the  corpus  callosum  antero- 
posteriorly  you  first  see  at  the  centre  the  divided  surface 
of  the  grand  commissure  ;  below,  the  septum  lucidum,  the  in- 
ternal face  of  the  thalamus  opticus,  then  the  cut  surfaces  of  the 
crura  cerebri. 

Better  to  obtain  our  points  of  compass,  we  will  start  from  a 


1  Edinburgh  Med.  Jour.,  Nov.,  1874,  p.  394. 

2  West  Riding  Asylum,  t.  IV.,  pp.  49  and  50,  Proceedings  of  the  Royal  Society, 
No.  151,  1874.     British  Medical  Journal,  Dec.  19,  1874. 


28  DISEASES   OF   THE   BRAIN. 

familiar  landmark  upon  the  external  face  of  the  brain,  that  is, 
the  fissure  of  Rolando,  and  follow  it  to  its  extreme  internal 
end.  This  furrow  sometimes  stops  a  little  short  of  the  inter- 
hemispheric  fissure ;  at  other  times  it  extends  quite  to  it, 
making  a  sort  of  notch  on  its  superior  border. 

The  paracentral  lobule  is  located  immediately  below  that 
point.  It  is  bounded  as  follows  :  posteriorly,  by  an  oblique 
fissure,  which  is  the  posterior  prolongation  of  the  calloso-mar- 
ginal  (that  fissure  extended  constitutes  the  posterior  border 
of  the  ascending  parietal  convolution) ;  below,  by  that  horizon- 
tal portion  of  the  calloso-marginal  fissure  which  separates  it 
from  the  convolution  of  the  corpus  callosum  (called  gyrus 
fornicatns)  ;  anteriorly,  by  a  fissure  generally  shallow,  but 
which  sometimes  continues  upon  the  internal  face  of  the  hemi- 
spheres and  which  anteriorly  marks  the  internal  part  of  the 
ascending  frontal  convolution  and  bounds  the  anterior  face  of 
the  paracentral  lobule. 

Thus  we  have  a  small  quadrilateral  lobule  whose  greatest 
diameter  is  antero-posterior.  Generally  a  shallow  furrow, 
midway  between  the  upper  and  lower  borders,  runs  the  entire 
length  of  the  lobule.  By  reason  of  its  structure,  as  much  as 
from  its  position,  it  may  be  said  that  the  paracentral  lobule 
seems  to  represent  upon  the  median  face  of  the  hemisphere 
the  inverse  surfaces,  the  internal  extremities  of  the  two  ascend- 
ing convolutions. 

This  point  fixed,  it  is  not  difficult  to  give  the  remaining 
topography  of  the  internal  face  of  the  hemispheres.  1st. 
Anterior  to  the  paracentral  lobule  is  seen  the  median  surface 
of  the  first  frontal  convolution.  2d.  Below,  and  separated 
from  the  preceding  by  the  calloso-marginal  furrow,  is  the 
convolution  of  the  corpus  callosum  (gyrus  fornicatus}.  3d. 
The  last-named  convolution  is  continued  posteriorly,  forming  a 
lobule  quite  circumscribed,  and  which  is  called  the  quadrilat- 
eral lobule  (avant  coin,  Vorzwickel,  prcecuneus).  This  lobule 
we  may  consider  as  the  internal  or  median  face  of  the  su- 
perior parietal  lobule.  Behind  this  the  temporo-occipital  fis- 
sure (very  marked  at  this  point,  because  it  is  not  interrupted, 
as  upon  its  external  face,  by  overlying  convolutions)  separates 


NORMAL   STRUCTURE   OF   THE   CONVOLUTIONS.  29 

very  clearly  the  quadrilateral  lobule  from  the  occipital  lobe. 
4th.  Immediately  behind  the  quadrilateral  lobule  in  the 
region  of  the  occipital  lobe,  there  is  a  triangular  lobule,  the 
point  of  which  is  inferio-anterior,  the  base  posterio-superior, 
and  which  is  bounded  posteriorly  by  a  deep  fissure,  theftssura 
calcarina ;  that  little  lobule  is  called  the  cuneus  (com, 
zwickel}.  5th.  Below  that  triangle  you  observe  the  lack  of 
demarcation  already  noticed  upon  the  external  surface  be- 
tween the  occipito-sphenoidal  lobes.  In  this  region  should 
be  specially  observed  two  convolutions  running  antero-pos- 
teriorly.  They  are  :  (a)  the  lateral  occipito-sphenoidal  lobule 
(lobulus  fusiformis)  ;  (b)  the  median  occipito-sphenoidal 
lobule  (lobulus  lingualis).  6th.  Still  in  front,  and  fully  within 
the  sphenoidal  lobe,  is  the  gyrus  hippocampi,  the  hook 
(crochet)  which  constitutes  part  of  the  horn  of  Ammon  (cornu 
Ammonis). 

As  we  proceed  we  shall  most  certainly  have  occasion  to 
use  the  topographical  knowledge  which  we,  are  obtaining,  and 
I  hasten  to  complete  the  description,  which  in  some  respects 
is  a  digression. 

C.  I  therefore  return  to  the  paracentral  lobule  and  to  the 
ascending  convolutions.  These  have  already  a  history  in 
experimental  pathology,  and  further  on  it  will  be  shown  that 
they  have  also  a  history  in  human  pathology.  I  am  not 
aware  whether  with  the  monkey,  at  least  with  the  higher 
grade  of  monkey,  the  paracentral  lobule  (which  exists  as  with 
man)  has  ever  been  the  object  of  physiological  investigations. 

(a.)  I  may  here  cite  a  case,  unique  of  its  kind  to  be  sure, 
but  which  nevertheless  will  for  the  future  lend  an  interest 
to  this  lobule  as  connected  with  human  pathology.  This 
instance,  of  which  I  give  an  outline,  has  been  recorded  by  an 
attentive  observer,  Sander.1 

A  child  who  died  at  the  age  of  fifteen  had  been  attacked  in 
the  third  year  of  its  age  with  infantile  spinal  paralysis.  The 
malady  had  included  and  more  or  less  atrophied  all  the  limbs, 
and  especially  those  of  the  left  side.  Autopsy  revealed  in 

1  Centralblatt,    1875. 


30  DISEASES   OF  THE   BRAIN. 

the  spinal  cord  all  the  lesions  described  by  the  French  authors. 
A  minute  examination  of  the  brain  led  to  the  discovery  that 
the  two  ascending  convolutions  upon  the  external  face  were 
very  much  shorter  than  normal.  They  left  the  island  of  Reil 
somewhat  uncovered,  besides  which  they  were  destitute  of 
folds.  The  paracentral  lobule  was  entirely  rudimentary,  in 
this  respect  markedly  in  contrast  with  all  the  other  convolu- 
tions, which  were  perfectly  developed.  Lastly,  the  lesions 
were  most  pronounced  in  the  right  hemisphere,  which  is  in 
keeping  with  the  circumstance  that  the  spinal  lesions  were 
most  marked  upon  the  left  side. 

The  author  expresses  the  opinion  that  in  this  case  the  limbs 
having,  at  an  early  age,  suffered  complete  paralysis,  resulting 
from  a  profound  spinal  lesion,  the  psycho-motor  centres, 
struck  with  inertia  at  a  time  when  they  were  in  process  of 
evolution,  had  in  consequence  been  arrested  in  development. 
The  interpretation  seems  worthy  of  consideration.  It  is  much 
to  be  regretted  that  the  condition  of  the  nerve-cells  in  the 
psycho-motor  centres  was  not  ascertained. 

A  case  observed  by  Luys  to  a  certain  extent  resembles  the 
foregoing.  In  a  subject  where  amputation  had  been  made, 
some  years  previous  to  autopsy,  my  colleague  at  la  Salpe- 
triere  noted  an  atrophy  of  the  cerebral  convolution  on  the 
side  opposite  to  the  amputation.  Unfortunately  the  exact  seat 
of  the  atrophy  was  not  (to  my  knowledge,  at  least)  given. 

(#.)  I  am  thus  led  to  introduce  another  fact  concerning  that 
part  of  the  brain  with  which  we  are  occupied.  According  to 
the  researches  of  Betz,  the  giant  pyramidal  cells  exist  but  in 
small  number  with  very  young  infants  ;  it  is  only  later  that 
their  number  increases,  and  that  increase  is  effected,  accord- 
ing to  all  appearances,  under  the  influence  of  functional 
exercise. 

This  fact  is  worthy  of  being  joined,  on  the  one  hand,  with 
that  of  Sander's,  and  on  the  other  hand  to  an  observation  of 
an  experimental  order  recently  recorded  by  Soltmann.1  That 
author  (and  I  believe  that  Professor  Rouget,  of  Montpellier, 

1  Reizbarkeit  der  Grosshirnrinde,  in  Centralblatt,  1875,  No.  14. 


NORMAL   STRUCTURE   OF  THE   CONVOLUTIONS.  31 

has  recorded  something  similar)  has  observed  that  with  newly 
born  dogs  the  excitation  of  regions  corresponding  to  the  psy- 
cho-motor points  produces  no  muscular  movement  in  the 
corresponding  limbs,  whereas,  some  time  after  birth,  towards 
the  ninth  or  eleventh  days,  these  points  become  excitable. 

These  observations,  though  yet  few,  should  nevertheless 
be  taken  into  account,  and  they  would  seem  to  indicate  that 
the  psycho-motor  centres  are  not  pre-established,  if  one  can 
so  speak,  so  much  anatomically  as  they  are  physiologically. 
They  are  developed  by  age,  doubtless  through  functional 
exercise. 

In  support  of  this  view  I  offer  a  remark  with  which  I  will 
terminate  the  special  subject  that  has  detained  us.  The 
regions  of  the  large  cells  belong  to  the  five-layer  type,  and 
these  regions  have  no  definite  anatomical  characteristic  except 
the  presence  of  giant-cells.  Now  these  giant-cells,  morpho- 
logically, do  not  differ  essentially  from  the  large  pyramidal 
cells,  which  also,  according  to  the  researches  of  Koschewnikoff, 
possess,  like  them,  the  nerve-prolongations  in  addition  to  the 
protoplasmic  prolongations,  attributed  to  motor  cells. 

It  seems  natural  to  inquire  if  these  cells,  and  even  those  of 
the  smaller  species,  which  are  their  miniature  representatives, 
would  not  be  capable,  under  certain  conditions — under  the 
influence,  for  example,  of  abnormal  functional  excitement — of 
acquiring  development,  and  in  that  way  giving  birth  to  sup- 
plementary motor  centres  destined  to  replace  primitive  cen- 
tres that  by  some  lesion  may  have  been  destroyed.  Thus, 
for  example,  might  be  explained  how  voluntary  movements 
can  be  restored  in  a  part,  notwithstanding  the  destruction  of 
a  motor  centre — a  phenomenon,  an  example  of  which  is  fur- 
nished in  the  frequent  recovery  from  aphasia,  in  despite  of 
the  persistence  of  the  lesion  of  the  third  frontal  convolution. 

D.  To  complete  the  examination  of  the  cerebral  cortex,  I 
have  but  to  add  some  little  information  upon  its  peculiarities 
in  the  posterior  region  of  the  brain. 

These  peculiarities  belong  to  the  entire  occipital  lobe,  the 
sphenoidal  lobe,  and  the  posterior  and  median  parts  of  the 
hemisphere  to  the  posterior  border  of  the  quadrilateral  lobule. 


32  DISEASES   OF  THE   BRAIN. 

The  general  character  of  the  gray  substance  in  those  regions 
is  that  the  pyramidal  nerve-cells,  as  a  rule,  are  very  scarce 
and  small,  while  the  granular,  on  the  contrary,  are  notably 
predominant.  It  is  not  that  there  are  no  large  nerve-cells, 
but  they  are  comparatively  rare — solitary ',  to  employ  the  ex- 
pression of  Meynert.  Betz  adds  that  they  have  no  nerve- 
prolongations,  and  that  even  the  protoplasmic  prolongations 
are  scarcely  developed. 

The  portion  of  the  brain  where  this  peculiarity  is  to  be 
observed  corresponds,  according  to  many  authors,  to  the  sen- 
sorium  commune.  If  this  interpretation  be  correct,  it  would 
follow  that  the  cells  of  which  we  are  about  to  speak  are  cells 
of  sensation.  This  hypothesis  rests  upon  still  other  anatom- 
ical considerations,  and  upon  pathological  evidence  of  which 
I  will  hereafter  give  more  detail. 


FOURTH    LECTURE. 

PARALLEL  BETWEEN  SPINAL  AND  CEREBRAL  LESIONS. 

Summary  : — The  Indispensable  Conditions  for  the  Study  of  Cerebral 
Localization  in  Diseases  in  Man.— Necessity  of  Good  Clinical  Observa- 
tions and  Regular  Autopsy. — Natural  History  of  Encephalic  Lesions. 
— Parallel  between  the  Grand  Compartments  of  the  Cerebro-gpinal 
Axis.— Systemization  of  Lesions  in  the  Spinal  Cord.— Spinal  Localiza- 
tions.—The  Brain  is  placed  under  a  Pathological  Regime  Differing 
from  other  Parts  of  the  Nerve-Axis ;  Rarity  of  Localizations. — Differ- 
ence of  Lesions.— Frequency  of  Vascular  Lesions  in  Maladies  of  the 
Brain.— Necessity  of  the  Study  of  Vascular  Distribution.— Outline  of 
the  Cerebral  Arteries. 

GENTLEMEN  : 

From  the  preceding  lectures  you  comprehend  that,  unpre- 
pared by  a  precise  knowledge  of  normal  anatomy,  it  would  be 
useless  to  undertake  this  subject. 

The  subordination  of  pathological  to  normal  anatomy  is 
most  especially  obvious  in  all  questions  related  to  cerebral 
pathology.  This  will  directly  be  rendered  still  more  evident. 

I.  To-day  we  will  commence  by  recounting  the  indispensa- 
ble conditions  for  solving  the  problems  connected  with  local- 
ization in  cerebral  diseases,  as  exhibited  in  man. 

The  following  are  the  fundamental  ones  :  1st.  A  good  clin- 
ical observation  made  with  the  most  complete  possible  knowl- 
edge of  existing  facts  in  experimental  physiology.  2d.  A 
regular,  anatomically  precise  autopsy. 

Our  preceding  topographical  studies  make  an  important 
step,  for  they  will  better  enable  us  to  determine  the  locations, 
extent,  and  configuration  of  lesions  revealed  by  autopsy. 

For  the  special  object  which  we  have  in  view,  however, 
even  the  most  minute  and  exact  anatomical  observations  can- 
3 


34  DISEASES   OF  THE   BRATN. 

not  always  be  utili/.eil.  IIiMv  as  elsewhere,  it  is  necessary 
that  observation  should  teach  us  how  to  select  from  things 
seen,  and  in  this  process  more  than  one  difficulty  must  be 
overcome. 

To  make  you  familiar  with  the  situation  it  is  best  first  to 
survey  the  natural  history  of  encephalic  lesions. 

\  st.  What  are  the  alterations  capable  of  affecting  the  en- 
cephalon,  or  especially  the  brain?  We  are  now,  of  course, 
dealing  only  with  the  most  usual  forms  of  cerebral  disease — 
with  partial  or  circumscribed  lesions  as  they  are  called  ;  such 
only  can  be  profitably  considered  in  this  connection. 

2d.  In  the  second  place,  wli.it  are  the  general  anatomical 
conditions  which  preside  either  at  the  development,  or  dur- 
ing the  process  of  reparation  of  such  lesions  ?  For  there  is 
no  chance  work,  even  in  the  encephalon. 

To  accomplish  our  end  I  propose  once  more  to  employ  the 
comparative  method,  that  lever  so  powerful  in  natural  sci- 
ences. I  will  make,  pathologico-anatomically,  a  comparison 
between  the  grand  cerebro-spinal  compartments  (or  if  you 
choose  Piorry's  nomenclature,  nem%-a.\'is)\  that  is  :  1st,  the 
spinal  cord ;  2d,  the  rac Indian  bulb  ;  3d,  the  brain  proper. 

A.  It  may  be  said  that  the  pathological  physiology  of  the 
spinal  cord  is  distinguished  by  the  extensive  existence  in  it 
of  those  lesions  called  systemic.  By  this  expression,  bor- 
rowed from  Vulpian,  are  meant  those  lesions  which  are  sys- 
temically  (the  term  is  perfectly  appropriate)  circumscribed, 
and  which  do  not  overstep  the  limits  of  certain  clearly  deter- 
mined regions  in  that  complex  organ.  I  beg  to  refer  you  to 
figure  No.  21,  which  will  recall  our  past  lectures. 

You  remember  that  there  are  lesions  limited  to  the  anterior 
cornua  of  the  gray  substance  (Fig.  7).  They  are,  in  acute 
form,  infantile  paralysis ;  in  chronic  form,  the  various  kinds 
of  progressive  locomotor  ataxia.  There  are  other  lesions 
limited  to  the  lateral  fasciculi  and  which  are  distinguished  by 
symptoms  of  numbness  (paresie)  with  a  tendency  to  contrac- 
tions. You  know  that  the  fibres  of  Goll  may  alone  be  sub- 
ject to  lesions ;  and  that  the  regions  of  the  little  external  bands 
(Fig.  7)  (posterior  columns)  in  the  area  of  the  lateral  fasciculi 


SPINAL    AND    CEREKRAL    LESIONS. 


35 


is  the  only  anatomical  substratum  necessary  for  symptoms 
of  spiiuil  tabes. 

It  is  thus  that  pathological  anatomy,  guided  in  its  first  steps 
by  experiment  with  animals,  and  aidi-d  also  by  clinical  ex- 
perience, has  become  able  to  separate,  in  man,  the  complex 
organ  called  the  spinal  cord,  into  a  certain  number  of  com- 
partments, departments,  and  secondary  organs. 


Posf.Cornuj 


\Post;.  Cornxu 


/fibers  of  Goll. 
FIG.  7. — Transverse  section  of  spinal  cord. 


To  each  systemic  lesion  of  these  various  regions  belong 
groups  of  symptoms  or  syndromes  which  clinically  serve  to 
individualize  them,  and  which  have  also  given  place,  in  path- 
ological descriptions  of  the  spinal  cord,  to  a  certain  number 
of  elementary  affections.  Analysis,  founded  upon  a  knowl- 
edge of  the  elementary  affections,  is  a  great  help  in  unveiling 
mixed  or  complex  forms. 

The  study  of  these  systemic  lesions  has  doubtless  contrib- 
uted greatly  to  rescue  spinal  localization  from  its  past  chaos. 

B.  Systemic  lesions  are  found  extended  to  the  rachidian 
bulb,  the  protuberance,  and  the  crura  cerebri.  I  will  cite  for 
examples  the  secondary  degenerations  of  the  cord  consecutive 
to  lesions  of  the  brain,  primitive  and  symmetrical  sclerosis  of 


36  DISEASES   OF  THE   BRAIN. 

the  lateral  column,  bulbous  paralysis  from  exclusive  lesion 
of  the  ganglia  at  the  origin  of  the  nerves,  etc.  But  above 
that  point  this  mode  of  pathological  alteration  does  not  ap- 
pear to  exist,  and  it  may  be  said  that  to  the  present  systemic 
lesions  in  the  brain  are  unknown. 

No  one  really  knows  of  systemic  lesions  limited  to  the 
thalami  optici,  to  the  different  ganglia  of  the  corpora  striata, 
or  to  the  various  portions  of  the  cortex.  It  does  not  follow, 
however,  that  strict  research  cannot  determine  anatomical 
localizations  in  the  encephalon,  but  they  are  at  present  rela- 
tively rare,  and  seemingly  accidental. 

What  is  the  real  reason  of  this  singular  fact  ?  It  is  that  the 
encephalon  is  placed  under  a  pathological  regime,  so  to  speak, 
differing  from  that  controlling  other  portions  of  the  nerve- 
axis.  In  fact,  speaking  in  a  general  way,  in  the  encephalon, 
and  especially  in  the  brain,  the  vascular  system  (arteries, 
veins,  and  capillaries)  commands  the  situation. 

I  will  call  attention  to  the  importance  of  vascular  ruptures 
and  ensuing  hemorrhage  in  the  intra-encephalic  centres ; 
the  predominant  role  of  vascular  obliterations  by  thromboses 
and  emboli,  the  effect  of  which  is  extravasation  followed  by 
partial  softening  of  the  brain. 

I  will  enumerate  the  most  common  anatomical  causes  of 
organic  disease  in  the  encephalon. 

C.  If  we  now  return  to  the  spinal  cord  and  bulb,  we  will 
observe  a  remarkable  contrast  to  the  encephalon.  Hemor- 
rhage by  vascular  rupture,  whether  resulting  from  the  altera- 
tion well  known  under  the  name  of  miliary  aneurism,  from 
softening  consecutive  to  arterial  narrowing,  or  from  throm- 
bosis or  embolism,  is  something  which  in  the  spinal  cord  is 
almost  unknown. 

The  bulb  constitutes,  as  it  were,  the  transition  between  the 
spinal  cord  and  the  encephalon,  for  in  the  bulb  is  seen,  on 
the  one  hand,  systemic  lesions  which  recall  those  seen  in  the 
cord,  and  on  the  other  hand,  a  certain  number  of  hemor- 
rhages and  softenings  are  found  resulting  from  vascular 
lesions. 

These  last,  however,  are  still  more  frequent  in  the  protube- 


SPINAL   AND   CEREBRAL  LESIONS.  37 

ranee,  the  pathology  of  which  also  approaches  more  nearly 
that  of  the  encephalon.  Hemorrhage  from  rupture  of  mili- 
ary  aneurism,  and  softening  by  vascular  obliteration,  here 
become  frequent. 

D.  These  considerations  explain  why  the  most  common 
anatomical  localization  in  the  encephalon  is  to  be  arrived  at 
chiefly  through  a  knowledge  of  the  vascular  distribution  ; 
for  the  broken  vessel  being  known,  one  can,  as  Lepine  has 
truly  said,  decide  the  outline  and  extent  of  the  territory 
involved. 

This  directs  us  once  more  to  the  field  of  normal  anatomy, 
for  the  purpose  of  obtaining  some  general  ideas  relative  to  the 
vascularization  of  the  encephalon.  This  is  a  subject  worthy 
of  your  entire  attention,  the  more  so  that  the  questions  relat- 
ing thereto  have  been  thoroughly  investigated,  and  to  this 
your  countrymen  have  contributed  their  share. 

II.  For  the  present  it  will  suffice  to  examine  the  arterial 
system,  although  lesions  of  the  venous  system  have  also  a 
marked  influence  upon  the  development  of  encephalic  altera- 
tions. The  immediate  object  is  to  show  by  some  examples 
how  important  a  profound  knowledge  of  the  normal  conditions 
of  cerebral  circulation  is  to  the  understanding  of  the  majority 
of  anatomical  lesions  of  the  brain. 

You  remember  the  manner  in  which  the  trunks  of  the  two 
internal  carotids  and  the  two  vertebral  arteries  join  at  the 
base  of  the  encephalon  to  carry  on  the  circulation.1 

The  internal  carotids,  as  they  leave  the  cavernous  sinus,  run 

1  It  is  known  that  hemorrhage  and  softening  of  the  brain  are  much  more  fre- 
quent on  the  left  than  on  the  right  side.  Duret,  in  his  memoire,  thinks  to  have 
discovered  the  anatomical  solution  of  this  fact  in  the  manner  in  which  the  primitive 
carotid  and  the  vertebral  arteries  of  the  left  side  originate.  The  right  carotid 
arises  from  the  innominate,  and  the  innominate,  at  a  considerable  angle,  from  the 
axis  of  the  aorta,  whereas  the  left  carotid  ascends  nearly  perpendicularly,  and  its  axis 
is  more  nearly  continuous  with  the  ascending  aorta.  It  follows  that  a  clot  expelled 
by  a  cardiac  contraction  would,  by  a  direct  line,  be  more  apt  to  enter  the  left  carotid. 
The  right  vertebral  artery  rises  from  the  horizontal  portion  of  the  subclavian 
after  it  has  made  its  curve  ;  the  left  vertebral  artery,  on  the  contrary,  takes  its  rise 
from  the  summit  of  the  curve  of  the  subclavian. 


3« 


DISEASES   OF  THE   BRAIN. 


perpendicularly  to  the  base  of  the  brain,  and  immediately 
divide  into  two  branches,  the  one  anterior  (the  anterior  cere- 
bral), the  other,  running  laterally,  bears  the  name  of  Sylvian, 
or  middle  cerebral  artery  (Fig.  8).  Near  their  origin  the  two 
anterior  cerebral  arteries  are  transversely  united,  and  thus,  in 
a  more  or  less  complete  manner,  the  circulation  of  the  two 
internal  carotids  are  unified.  That  vascular  arrangement  con- 


Verted.  Arteries. 
[  FIG.  8. — Scheme  of  arterial  circulation  at  the  base  of  the  encephalon. 


stitutes  a  special  system,  to  which  may  be  given  the  name  of 
anterior  system,  or  carotid  system. 

The  vertebral  arteries,  directed  obliquely  from  behind  for- 
ward, converge  towards  the  median  line  and  unite  in  a  single 
trunk,  the  basilar  trunk.  Towards  the  anterior  border  of  the 
protuberance,  this  basilar  trunk  separates  into  two  branches, 


SPINAL  AND   CEREBRAL  LESIONS.  39 

called  the  posterior  cerebral  arteries,  and  these  constitute  a 
second  arterial  system,  the  posterior,  or  vertebral  system. 

The  carotid  system  and  the  vertebral  system,  united  by  two 
vessels  called  the  posterior  communicants,  and  which  are  quite 
variable  in  volume  and  arrangement,1  form  a  vascular  circle 
at  the  base  of  the  brain,  known  to  all  anatomists  under  the 
name  of  the  hexagonal,  or  better,  the  polygon  of  Willis. 

At  the  anterior  angles  of  the  polygon  of  Willis  are  the  two 
anterior  cerebral  arteries ;  from  the  antero-lateral  angles, 
running  outwards,  arise  the  two  Sylvian  (middle  cerebral) 
arteries,  and  finally,  the  posterior  angle  is  formed  by  the 
posterior  cerebral  arteries.  This  is  the  circle  of  Willis,  and  the 
first  two  centimetres  of  those  various  arterial  trunks  give  rise 
to  the  nutrient  arteries  of  the  central  ganglia,  the  corpora 
striata  and  thalami  optici. 

There  are  six  principal  groups  of  these  nutrient  arteries. 

The  first — antero-median  group — has  its  origin  in  the  ante- 
rior communicant  and  in  the  commencement  of  the  anterior 
cerebral  arteries.  The  arterioles  of  which  it  is  composed 
nourish  the  anterior  part  of  the  head  of  the  caudated  ganglion. 

The  second — postero-median  group — arises  irom  the  pos- 
terior half  of  the  posterior  communicants,  and  from  the  origin 
of  the  posterior  cerebral  arteries.  They  nourish  the  internal 
face  of  the  thalami  optici  and  the  walls  of  the  third  ventricle. 

The  third  and  fourth — right  and  left  antero-lateral  groups 
— composed  of  a  larger  number  of  arterioles,  rise  from  the 
Sylvian  arteries  and  supply  the  corpora  striata  and  the  ante- 
rior part  of  the  thalami  optici. 

The  fifth  and  sixth — postero-lateral  groups  —  are  derived 
from  the  posterior  cerebral  arteries  after  they  have  passed 
around  the  crura  cerebri ;  they  nourish  a  great  part  of  the 
thalami  optici. 

A  line  surrounding  the  circle  of  Willis,  two  centimetres  out- 

1  Duret  has  directed  attention  to  the  frequent  variations  and  anomalies  of  the 
circle  of  Willis  and  the  communicants.  These  last  are  often  filiform  and  entirely 
insufficient  to  re-establish  circulation  in  case  of  obliterations.  Certain  forms  of 
anomalies  explain  also  cases  of  softening  of  an  entire  hemisphere,  by  a  clot  obliter- 
ating the  internal  carotid  near  its  bifurcation. 


4O  DISEASES   OF  THE  BRAIN. 

side  of  it,  would  include  the  origin  of  the  ganglionic  arteries, 
and  it  might  also  be  termed  the  ganglionic  circle  (Fig.  8). 

The  cortical  regions  (the  convolutions  of  the  cerebral  hemi- 
spheres) are  irrigated  by  the  large  arteries  which  form  the 
angles  and  sides  of  the  circle  of  Willis. 

The  anterior  cerebral  artery  winds  around  the  corpus  cal- 
losum,  and  spreads  upon  a  portion  of  the  inferior  face  of  the 
anterior  or  frontal  lobe  (gyms  rectus  andgyri  supra- orbit  ales] 
and  over  a  larger  portion  of  the  internal  face  of  the  hemi- 
sphere (first  and  second  frontal  convolutions,  prcecentral  and 
quadrilateral  or  prcecuneus  lobules. ) 

The  posterior  cerebral  artery ',  springing  from  the  basilar, 
winds  around  the  corresponding  cerebral  peduncle,  and  divides 
into  three  branches,  which  go  to  the  inferior  face  of  the  brain 
and  to  the  occipital  lobe  (gyms  uncinatus ;  gyrus  hippo- 
campi ;  second,  third  and  fourth  temporal  convolutions  ;  the 
cuneus  ;  lobulus  lingualis). 

The  Sylvian  (middle  cerebral)  artery  is  distributed  to  that 
part  of  the  frontal  lobe  which  is  not  vascularized  by  the 
anterior  cerebral  artery,  and  over  the  entire  parietal  lobe. 
Later  it  will  be  necessary  to  follow  in  detail  the  distribution 
of  each  of  the  four  branches  of  this  important  artery,  and  to 
describe  exactly  their  vascular  territories. 

Such,  then,  is  the  general  distribution  of  the  arteries  sent 
to  the  internal,  external,  and  inferior  faces  of  the  brain.  To 
understand  the  interior  vascular  arrangement  it  is  necessary 
to  have  recourse  to  various  sections.  Upon  a  single  section 
made  within  the  domain  of  the  Sylvian  artery,  the  circulation 
in  the  gray  ganglia  will  seem  to  be  confounded  with  that  of 
the  surrounding  gray  matter  and  the  subjacent  white  ganglia  ; 
that  is  but  an  illusion,  however,  which  will  be  dispelled  in 
the  next  lecture. 


FIFTH  AND  SIXTH  LECTURES. 

ARTERIAL   CIRCULATION    IN   THE   BRAIN. 

Summary  :— Labors  of  Duret  and  Heubner.— Principal  Arteries  of  the 
Brain.— The  System  of  Cortical  Arteries.— Nutrient  Vessels.— System 
of  the  Central  Arteries,  or  of  the  Central  Ganglia.— Sylvian  Artery  ; 
Its  Branches;  Arteries  of  the  Central  Gray  Ganglia;  Cortical 
Branches ;  Ramifications  and  Arborizations  ;  Nutrient  Arteries  of 
the  Encephalic  Pulp;  they  are  Long  (Medullary  Arteries)  and  Short 
(Cortical  Arteries).— Effects  of  Obliterations  of  the  Various  Arteries. 
—Superficial  Softenings,  Yellow  Spots— Communication  between  the 
Vascular  Territories;  Opinion  of  Heubner;  Opinion  ofl>uret. — Ter- 
minal Arteries  (Cohnheim) — Relative  Autonomy  of  the  Vascular 
Territories  of  the  Brain. — Localizations  of  Cortical  Lesions. — Branch- 
es of  the  Sylvian  Artery  ;  Frontal,  External,  and  Inferior.— Artery  of 
the  Ascending  Frontal  Convolution.— Artery  of  the  Ascending  Parie- 
tal Convolution.— Artery  of  the  Gyrus  Angularis.— Anterior  and  Pos- 
terior Cerebral  Arteries  ;  their  Branches. 

GENTLEMEN  : 

To-day  I  propose  to  examine  more  thoroughly  the  subject 
which  was  barely  introduced  in  our  last  lecture.  If  I  have 
clearly  shown  that  in  cerebral  pathology  it  is  the  arterial 
system  which  commands  the  situation,  I  must,  as  a  matter 
of  course,  through  the  same  effort,  have  proved  the  necessity 
of  preliminary  studies  concerning  the  physiological  connec- 
tion between  the  circulation  and  the  various  departments  that 
compose  the  brain  proper. 

How,  indeed,  can  one  comprehend  the  rationale  of  hemor- 
rhagic  centres,  or  centres  of  softening,  which  constitute  the 
chief  pathological  anatomy  of  the  brain,  if  he  is  not  entirely 
familiar  with  the  special  distribution  of  the  arterial  vessels, 
an  alteration  in  which  is  the  commencement  or  the  first  con- 
dition of  these  various  lesions. 

Unapplied  facts  in  normal  anatomy  will  not  here  suffice. 
But  the  application  of  them  at  once  suggests  itself.  I  have 


42  DISEASES   OF  THE   BRAIN. 

already  shown  this,  and  I  shall  now  exhibit  it  still  more 
clearly. 

I  pause  at  this  point  in  the  anatomy  of  cerebral  circu- 
lation, because  that,  even  in  the  works  most  justly  esteemed, 
you  will  find  on  this  subject  only  the  most  vague  and  en- 
tirely insufficient  information,  quite  inadequate  to  our  needs. 

All  the  precise  knowledge  which  we  have  is  of  recent  date, 
and  is  the  result  of  studies  exacted  through  the  needs  of 
pathological  anatomy  and  physiology. 

I  shall  borrow  particularly  from  the  important  work  of  our 
countryman,  Duret — a  work  which  has  been  executed  in  the 
laboratory  of  Salpetriere.  Duret  has  encountered  a  rival  in 
his  field.  That  rival  is  a  German  doctor,  Heubner,  professor 
at  the  Leipzig  University.  These  two  authors,  unacquainted 
with  each  other,  have  pursued  their  researches  simultaneously, 
and  in  the  most  essential  points  they  have  arrived  at  identi- 
cal results.  That  assuredly  is  a  guarantee  of  the  exactness 
of  the  descriptions  which  they  have  given  us. 

In  a  recent  work  treating  of  syphilitic  alterations  in  the 
cerebral  arteries,1  Heubner  professes  to  have  been  the  initia- 
tor. That  is  a  claim  which  cannot  be  sustained.  The  first 
researches  of  Duret  relative  to  the  circulation  in  the  bulb  and 
the  protuberance  were  communicated  to  the  Societe  de  Bio- 
logic in  the  session  of  Dec.  7,  1872. 

By  a  remarkable  coincidence,  the  same  day,  the  7th  of 
December,  the  resume  of  the  researches  of  Heubner  upon 
cerebral  circulation  was  published  at  Berlin  in  the  Central- 
blatt.  One  month  after,  in  January,  1873,  Duret  published 
a  note  in  the  Pr ogres  medical*  concerning  that  part  of  his 
researches  which  treated  also  of  the  cerebral  circulation.  The 
investigations  of  Duret  are  not,  then,  two  years  later  than 
those  of  Heubner,  as  the  latter  insinuates  ;  they  are  exactly 
contemporaneous.  Of  this  fact  Heubner  might  easily  have 
convinced  himself,  as  he  has  become  acquainted  with  the  last 
memoire  of  Duret,  published  in  the  Archives  de  physiolo- 


1  Die  luetische  Erkrankung  der  Hirnarterien,  p.  188,  Leipzig,  1874. 

8  i8th  and  25th  of  January,  ist  of  February,  8th  and  i$th  of  November,  1873. 


ARTERIAL   CIRCULATION   IN  THE  BRAIN.  43 

gie  (1874),  where  the  history  of  the  question  is  given  in  de- 
tail.1 

I  have  thought  it  well  to  insist  upon  this  chronology,  in 
face  of  the  annexation  mania,  in  order  to  establish  the  large 
part  which  belongs  to  our  countryman. 

I.  I  come  to  the  special  object  of  our  studies.  You  know 
the  manner  in  which  the  three  trunks,  rising  from  the  circle 
of  Willis,  divide  among  themselves  the  arterial  circulation  in 
each  cerebral  hemisphere.  They  are  :  ist,  the  anterior  cere- 
bral ;  2d,  the  middle  cerebral  or  Sylvian  artery,  each  rising 
from  the  internal  carotid  ;  3d,  the  posterior  cerebral,  branches 
from  the  basilar,  a  single  trunk  formed  by  the  confluence  of 
the  two  vertebral  arteries. 

A.  Each  one  of  these  arteries,  in  each  hemisphere,  com- 
mands  a  special  province  ;   I  have  already  briefly  acquainted 
you  with  the  general  topography  and  limits  of  these  main 
vascular  territories,  and  they  should  be  examined  not  only 
at  the  surface  of  the  hemispheres,  but  also,  by  aid  of  sections, 
in  their  interiors. 

Our  attention  should  first  be  given  to  the  surface  of  the 
brain,  including  the  external,  superior,  internal,  and  inferior 
faces,  and  secondly  to  frontal  sections,  which  will  demon- 
strate the  preponderating  importance  of  the  Sylvian  territory. 

We  will  soon  see  that  these  territories  or  provinces  can  be 
divided  into  a  certain  number  of  secondary  departments, 
corresponding  to  the  distribution  of  so  many  secondary  ar- 
teries emanating  from  the  principal  trunks. 

B.  Without  stopping  longer  at  this  first  general  view,  we 
will  enter  at  once  into  details.     Each  one  of  the  .three  prin- 
cipal arteries  gives  rise  to  two  very  different  systems  of  secon- 
dary vessels.     The  first  of  these  may  be  denominated  the 
system  of  cortical  arteries.     The  vessels  of  which  it  is  com- 

1  The  researches  of  Duret  possess  a  considerable  pathological  interest,  for  they 
have  been  made  especially  to  explain  the  appearance  of  lesions  found  in  autopsies. 
With  the  aid  of  more  than  two  hundred  cases  furnished  him  by  Charcot,  he  has 
been  able  to  establish  an  anatomical  classification  of  cerebral  hemorrhages  and 
softenings. 


44  DISEASES   OF  THE   BRAIN. 

posed  are  spread  through  the  pia  mater,  and  there  divide, 
after  a  peculiar  method,  before  furnishing  the  little  vessels 
which  penetrate  the  cerebral  pulp,  and  which  are  really  the 
nutrient  vessels  of  the  gray  matter  and  the  subjacent  medul- 
lary substance. 

The  second  system  is  the  central  system,  or  the  system  of 
the  cerebral  ganglia  {gray  central  masses).  The  vessels  of 
which  it  is  composed  rise  from  each  of  the  three  principal 
arteries  close  to  their  origin,  and,  in  the  form  of  arterioles, 
plunge  immediately  into  the  substance  of  the  ganglionic 
masses. 

The  two  systems,  although  they  have  a  common  origin,  are 
entirely  independent  of  each  other,  and  at  the  border  of  their 
domains  they  have  no  point  of  intercommunication. 

C.  We  must  study  the  two  systems  in  each  of  the  main 
vascular  territories.  In  doing  this  we  will  observe  both  com- 
mon and  special  traits.  We  will  first  examine  the  Sylvian 
artery,  the  most  important  and  the  most  complicated  of  the 
three  cerebral  arteries  ;  after  that  the  description  of  the  two 
others  will  be  simple. 

II.  The  Sylvian  artery  enters  the  fissure  of  Sylvius,  the  lips 
of  which  must  be  separated  in  order  to  bring  the  vessel  well 
in  view.  But  before  this  it  furnishes  from  its  superior  border, 
in  a  region  called  the  anterior  perforated  space  (locus  perfo- 
ratus  antictis),  a  series  of  arteries  which,  running  parallel  to 
each  other,  enter  each  of  the  channels  of  the  perforated  space, 
which  space  is  composed  of  the  white  substance  (substantia 
perforata) .  These  are  the  arteries  of  the  central  gray  ganglia , 
or  more  definitely,  the  arteries  of  the  corpora  striata.  Let 
us  here  examine  the  cortical  system,  leaving  for  the  moment 
the  gray  ganglia. 

At  the  bottom  of  the  fissure  of  Sylvius  is  seen  the  island 
of  Reil,  on  a  level  with  which  the  Sylvian  artery  divides  into 
four  branches,  each  of  which  deserves  a  special  name.  These 
branches  follow  the  furrows  that  separate  the  convolutions  of 
the  island  and  to  which  they  furnish  vessels.  They  then  bend 
inwards  and  outwards,  and  rise  again  to  the  surface  of  the 


ARTERIAL   CIRCULATION   IN  THE   BRAIN. 


45 


hemisphere,  where  they  are  distributed,  as  we  have  just  said, 
over  a  certain  number  of  fundamental  convolutions,  where 
they  form  a  number  of  little  secondary  territories  correspond- 
ing to  each  one  of  the  convolutions.  (Fig.  9.) 


cowvol"  ,  Ascending  frontal  convolution 

j'S-- frontal  convolution. ; 

jl^frontal  convolution 
Ascending  Iparietal  conjrolTi        <*apT  panef  al  lobule . 


Trunk  of, 
Sylvian  ar._.^ 
Ext  •  &  inf r.  frontal  hrandh 
Ascending  frontal  artery  ,i 


artery 


yPanelo-sphenoidal  &  sphenoids!  arteries 
[Ascending  parietal  artery 

FlG.  9. — Distribution  of  Sylvian  artery.     (Partially  schematic,} 

We  will  not  dwell,  however,  upon  this  description,  but  pro- 
ceed to  examine  more  thoroughly  the  manner  in  which  the 
cortical  arteries  are  divided  and  distributed  to  the  substance 
of  the  pia  mater  before  they  penetrate  the  cerebral  pulp. 

I  should  mention  that  the  branches  arising  from  the  Sylvi- 
an artery  immediately  subdivide  into  branches  of  the  third 
order,  to  the  number  of  two  or  three  for  each  secondary 
trunk.  These  tertiary  branchlets  constitute  a  kind  of  vascu- 
lar skeleton,  upon  which  is  grafted  a  system  of  arborizations ; 
that  is  a  special  and  very  original  system  of  small  vessels, 
which  arise  not  only  from  the  extremities  of  the  branches,  but 
also  from  the  trunks  themselves. 


46  DISEASES   OF  THE  BRAIN. 

Contrary  to  the  assertions  of  most  authors,  Duret  affirms 
that  these  arborizations  do  not  anastomose  with  each  other, 
although  the  branchlets  sometimes  communicate  with  those 
of  the  neighboring  territories.  (Fig.  10.) 


Medulla 


.eaullary 
hraiicEes 


FIG.  10. — Arterial  division  in  the  encephalon.     (Duret.) 

The  ramifications  and  arborizations  are  on  a  plane  with 
the  pia  mater.  On  the  internal  face  of  that  membrane  they 
give  off  the  nutrient  arteries,  which  enter  the  encephalic  pulp 
perpendicularly.  The  nutrient  vessels  here  are  all,  according 
to  the  definition  of  Ch.  Robin,  capillaries.  This  character 
distinguishes  them  from  the  vessels  of  the  central  ganglia, 
which  bury  themselves  in  the  white  substance  of  the  base  of 
the  brain  (anterior  perforated  space),  inasmuch  as  these  last 
retain  the  structure  and  dimensions  of  arteries. 

By  aid  of  sections  which  can  be  examined  microscopically, 
we  will  now  investigate  more  closely  the  peculiarities  of  these 
nutrient  arteries. 

Upon  section  of  an  entire  convolution,  made  perpendicu- 
larly to  the  surface,  there  appears,  first  at  the  periphery,  the 
gray  substance  which  is  like  a  festoon,  having  a  thickness  of 


ARTERIAL   CIRCULATION   IN  THE   BRAIN.  47 

two  or  three  millimetres ;  next  to  this  is  the  medullary  sub- 
stance composed  of  diverging  andcommissural  fibres,  binding 
one  convolution  to  another.  In  such  sections  what  is  found 
to  be  the  arrangement  of  the  arteries  ?  There  can  easily  be 
distinguished  two  kinds  of  nutrient  arteries  which  have  long 
since  been  recognized  by  many  authors,  and  particularly  by 
Todd  and  Bowman.  Of  these  arteries  one  kind  are  long  and 
the  other  short. 

1st.  The  long  arteries,  otherwise  called  the  medullary  ar- 
teries, arise  from  the  ramifications,  or  indeed  are  the  terminals 
of  the  arborizations.  A  dozen  or  fifteen  may  be  seen  upon 
a  section  of  a  convolution  ;  three  or  four  at  the  free  surface  ; 
the  others  distributed  upon  the  two  slopes  or  in  the  separating 
furrow.  The  arteries  at  the  summit  are  vertical — one  of  them 
generally  occupies  the  middle  part  of  the  convolution  ;  the 
arteries  on  the  slope  are  oblique  ;  those  which  occupy  the 
bottom  of  the  furrow  are  again  vertical.  These  arteries  pene- 
trate the  centrum  ovale  to  the  depth  of  three  or  four  centi- 
metres ;  they  proceed  without  intercommunicating,  except  by 
means  of  fine  capillaries,  and  in  that  way  constitute  so  many 
little  independent  systems.  At  their  terminations  they  ap- 
proach the  extremities  of  the  central  system  of  arteries,  but 
there  is  no  communication  whatever  between  the  two  systems. 

Thus  there  exists  upon  the  confines  of  the  two  domains  a 
sort  of  neutral  ground  where  nutrition  is  less  active.  This 
neutral  ground  is  more  especially  the  location  of  lacunal  senile 
softenings. 

2d.  The  short  nutrient  or  cortical  arteries  have  the  same 
origin  as  the  long  ones,  but  they  are  finer  and  shorter,  and 
end,  so  to  speak,  on  the  road.  Some  run  to  the  inner  border 
of  the  gray  layer,  to  the  edge  of  the  medullary  centre  ;  others 
are  of  less  extent,  and  terminate  in  the  gray  substance.  These 
short  arteries  give  rise  to  capillary  vessels  which,  conjoined 
with  those  emanating  from  the  long  arteries,  form  a  mesh  or 
web. 

In  the  convolutions  this  network  possesses  the  following 
characters  (Fig.  n):  1st.  The  first  layer  has  the  thickness 
of  a  half  millimetre  ;  it  is  but  slightly  vascularized  ;  2d.  The 


48  DISEASES   OF  THE  BRAIN. 

second  layer  corresponds  to  two  zones  of  nerve-cells  ;  there 
the  vascular  network  is  very  compact,  and  with  very  fine 
polygonal  interspaces  ;  3d.  At  the  edge  of  that  layer  the  in- 
terspaces become  larger ;  4th.  Finally,  in  the  medullary  sub- 
stance the  interspaces  become  still  larger  and  vertically 
elongated. 

Arteries  oftfie  con-ex, 

or  grey  substance  •»*••»  n 

A.  _        _  .     _          ^,;Me<3ulIary 
— *    /^Arteries, 


Arteries  of  the  comrmssural 
fissure  of  GratioleL 

FIG.  ii. — Arterial  distribution  in  the  cerebral  cortex. 

From  the  preceding  facts  it  follows  that,  as  concerns  the 
arterial  distribution,  the  gray  and  subjacent  white  cortex  are 
a  unit,  since  the  vessels  which  they  receive  are  derived  in 
common  from  the  arteries  which  traverse  the  pia  mater. 
Should  these  last  be  obliterated  at  a  given  point,  the  gray  and 
white  substance  would  suffer  simultaneously  in  the  correspond- 
ing parts,  and  would  be  subject  to  that  kind  of  mortification 
called  isckcemic  cerebral  softening.  The  reciprocal  relations 
of  the  parts  permit  a  scheme  of  superficial  softenings. 


ARTERIAL   CIRCULATION   IN   THE   BRAIN.  49 

Recall  the  general  distribution  of  the  nutrient  vessels. 
They  are  directed  parallel  to  each  other  like  so  many  lines 
towards  the  central  parts.  The  white  and  the  gray  regions 
of  the  cortex  can  then,  as  vascular  departments,  be  divided 
into  a  number  of  wedges,  the  bases  of  which  are  directed 
towards  the  encephalon,  and  the  apices  towards  the  central 
parts.  This  is,  indeed,  the  form  assumed  by  the  greater 
number  of  those  softenings  called  superficial.  That  at  once 
calls  to  mind  the  appearance  of  infarctus  of  the  spleen  and 
kidney.  If  the  softening  is  an  old  one — that  is,  of  several 
weeks'  standing — the  gray  substance  appears  depressed  in 
consequence  of  the  destruction  of  its  elements  and  the  con- 
comitant turning  up  of  the  subjacent  white  substance. 

The  superficial  portions  of  the  softening  produce  a  yellow 
spot.  The  yellow  color  belongs  exclusively  to  the  gray  sub- 
stance, the  subjacent  softened  white  substance  being  only 
blanched,  or  sometimes  lightly  tinted  with  yellow. 

A.  In   this  case  we  have  supposed  the  obliteration   of  a 
branch  of  the  second  or  third  order.     The  obliteration  of  the 
trunk  of  the  Sylvian  artery  itself  might  produce  necrosis  of 
all  the  gray  cortex  and  of  the  subjacent  white  cortex  also. 

The  central  parts  would  be  entirely  spared  if  the  oblitera- 
tion occurred  above  the  origin  of  the  arteries  of  the  corpora 
striata. 

B.  It  need  not  be  supposed  that  all  obliterations  of  this 
kind  would    necessarily  and  surely  produce   such  disastrous 
effects.     There  are  rare  cases  where,  in  fact,  such  obliteration 
of  a  branch  of  the  Sylvian  artery,  or  even  the  artery  itself 
(I  here  take  the  Sylvian  artery  as  example,  it  would  be  the 
same  for  the  anterior  or  posterior  cerebral  arteries) — there 
are  cases,  I  say,  in  which  the  obliteration  in  question  has  no 
appreciable,  or,  at  least,  but  passing  results. 

If  this  be  so,  it  follows  that  the  three  main  vascular  terri- 
tories into  which  the  brain  is  divided,  and  the  departments 
into  which  they  in  turn  are  separated,  are  not  strictly  isolated, 
individual  territories.  They  may  communicate,  and  indeed 
do  communicate  in  the  ordinary  manner.  But  are  these 
communications  easy  and  constant,  or,  on  the  contrary,  are 
4 


50  DISEASES   OF  THE  BRAIN. 

they  accidental,  indirect,  and  often  impracticable  ?  In  the 
solution  of  this  question  authors  are  at  variance. 

Heubner  holds  that  the  communications  in  question  are 
very  easy,  that  they  are  made  by  the  mediation  of  vessels  not 
less  than  a  millimetre  in  diameter.  He  rests  that  assertion 
upon  the  results  of  injections,  where  he  has  invariably  observed 
that  the  material  injected  into  any  one  of  the  departments  by 
the  principal  trunk,  or  by  the  branches,  always  rapidly  pene- 
trates the  other  territories. 

He  also  cites  pathological  cases  which  indicate  that  obliter- 
ation of  one  of  the  vessels  of  the  cortical  system  or  of  its 
branches  has,  during  life,  given  no  evident  symptom  ;  cases 
in  which  death  having  followed,  the  cerebral  pulp  in  the  parts 
corresponding  to  the  obliteration  has  at  autopsy  presented  no 
trace  of  softening. 

In  the  first  place,  as  to  the  pathological  facts  of  Heubner, 
we  must  recognize  that  they  are  real  ;  of  this  there  is  no 
doubt.  At  the  same  time,  to  judge  from  the  very  numerous 
observations  which  I  have  collected,  they  are  certainly  rare. 

On  the  other  hand,  it  is  certain  that  in  anatomy  things  are 
far  from  being  always  as  seen  by  Heubner.  The  observations 
of  Duret  in  that  field  have  been  numerous,  and  are  nearly 
always  in  accord. 

Here  is  briefly  what  we  learn  from  them  : 

Let  ligatures  be  placed  upon  each  of  the  three  principal 
arteries  at  the  base  of  the  encephalon  on  both  sides,  immedi- 
ately above  their  origin  in  the  circle  of  Willis.  Then  inject 
the  Sylvian  artery.  This  will  first  fill  the  Sylvian  territory, 
and  in  the  majority  of  cases  it  will  pass  beyond  its  limits. 
The  injected  material  invades  the  neighboring  parts  slowly, 
little  by  little.  This  invasion  is  made  from  the  periphery 
inwards  towards  the  centre  of  the  invaded  territory.  It  is 
effected  through  the  mediation  of  vessels  of  small  calibre  be- 
longing to  the  system  of  ramifications  having  diameters  of  but 
a  quarter  or  a  fifth  of  a  millimetre,  contrary  to  the  opinion 
of  Heubner,  who  holds  that  these  anterial  vessels  have  a  diam- 
eter of  one  millimetre. 

The  number   of  anastomoses   from   territory  to   territory 


ARTERIAL   CIRCULATION   IN  THE   BRAIN.  51 

are  also  quite  variable.  There  are  cases  where  one  of  the 
three  grand  territories  can  be  injected  isolatedly,  the  anasto- 
moses not  being  sufficient  to  permit  the  injection  to  enter  the 
adjacent  territories.  The  communication  which  may  occur 
at  the  periphery  of  a  vascular  territory  explains  why  the 
obliteration  of  a  main  trunk  often  results  in  the  softening  of 
only  the  central  parts  of  the  territory,  the  peripheral  portion 
remaining  untouched. 

Such  are  the  conclusions  of  Duret,  and  to  my  mind  they 
are  more  in  conformity  with  pathological  facts  than  those  of 
Heubner.  I  should  add  that  Cohnheim,  who  has  also  ex- 
perimented in  partial  injections  of  the  encephalic  arteries, 
agrees  with  Duret.  He  says  if  the  arteries  of  the  encephalon 
are  not  final  or  terminal  arteries  (we  will  explain  what  Cohn- 
heim means  by  that  term),  they  very  nearly  approach  that  type. 

Under  the  name  of  terminal  or  final  arteries  (Endarterien) 
Cohnheim1  ingeniously  catalogues  those  arteries  or  arteri- 
oles  which,  between  their  origin  and  the  capillaries,  neither 
furnish  nor  receive  any  anastomosing  branch.  An  example 
of  terminal  arteries  convenient  for  study  is  afforded  by  the 
tongue  of  the  frog,  upon  which  it  is  easy,  through  the  micro- 
scope, to  observe  (de  visit]  all  the  effects  of  an  obliteration. 
You  see  upon  these  schematic  designs  the  various  conse- 
quences of  the  obliteration  of  a  terminal  artery.  The  results 
are,  as  it  were,  certain.  If,  on  the  other  hand,  we  deal  with 
an  anastomosing  artery,  generally  the  circulation  is  easily  re- 
established below  the  point  of  lesion,  by  means  of  anastomo- 
ses. But  these  anastomoses  may  in  their  turn  be  obliterated, 
and  it  so  may  follow  that  an  artery  which  in  its  normal  state 
is  not  at  all  a  terminal  artery,  may  become  so  by  accident. 

The  encephalic  circulation  furnishes  a  great  many  examples 
of  terminal  arteries.  Thus,  without  including  the  ramifica- 
tions which  exist  in  the  pia  mater,  we  can  instance  the  nutri- 
ent arteries.  We  see,  too,  that  the  arteries  of  the  central 
ganglia  are  entirely  and  rigorously  constructed  on  that  model. 
The  same  type  is  found  in  all  other  circulatory  systems  where 

1  Untersuchungen  ueber  die  embolischeu  Processe.  Berlin,  1872. 


52  DISEASES   OF  THE   BRAIN. 

pathological  or  experimental  lesions  by  vascular  obliterations 
usually  result  in  what  is  termed  infarctus.  Such  are  the 
spleen,  the  kidney,  the  lung,  and  the  retina.  None  of  the 
viscera — and  this  observation  belongs  to  Cohnheim — where 
infarctus  is  not  the  rule,  have  the  terminal  mode  of  arterial 
distribution. 

But  we  will  return  to  the  relative  individualities  of  the 
vascular  territories  of  the  brain.  Those  individualities  do 
not  belong  exclusively  to  the  large  territories  ;  they  are 
found  also  in  the  secondary  departments,  which  correspond 
to  the  ramifications  of  arteries  of  the  second  and  third  order. 
Between  these  regions  of  the  secondary  order,  the  same  as 
with  the  larger  ones,  communications  are  possible,  but  gene- 
rally are  very  difficult.  It  follows  that  obliteration  of  one  of 
these  secondary  branches  might  have,  and  often  does  have, 
the  effect  of  inducing  limited  mortification  in  the  cortex. 
This  is  an  important  point  in  the  study  of  cerebral  localiza- 
tion. It  might  be  that  a  lesion  thus  limited  would  exactly 
correspond  to  one  of  the  convolutions,  or  to  a  group  of  convo- 
lutions, endowed  with  specific  properties,  manifesting  them- 
selves during  life  through  special  phenomena. 

You  can  readily  comprehend  that  strict  localization  of 
lesions  of  the  cortex,  produced  by  obliterations  of  arterial 
branches  of  the  second  or  third  order,  would  be  an  especially 
interesting  study,  when  occurring  in  the  Sylvian  region.  It 
is  in  that  large  field  that  experimentation  tends  to  place  the 
famous  motor  centres  ;  it  is  there  also  that  clinical  experience, 
aided  by  pathological  anatomy,  has  located  the  faculty  of 
articulate  language. 

So  it  is  important  that  we  should  be  well  acquainted  with 
the  principal  branches  rising  from  the  Sylvian  artery,  and 
closely  examine  their  distribution  in  the  fundamental  convo- 
lutions of  that  region. 

The  Sylvian  artery  divides  into,  or  at  least  gives  rise  to, 
four  principal  branches.  The  distribution  of  these  branches 
has  been  carefully  studied  by  Duret  and  by  Heubner.  (See 
Figs.  9  and  12.) 

The  first  Duret  calls  frontal-external  and  inferior.      That 


ARTERIAL   CIRCULATION   IN   THE   BRAIN. 


53 


is  really  the  artery  of  the  third  frontal  convolution  (convolu- 
tion of  Broca).  I  have  myself  several  times  seen  an  oblitera- 
tion of  this  arterial  trunk  produce  a  softening  confined  to  the 


'iQccipital 
lloba 

FIG.  12. — Vascular  territories  of  the  superior  cerebral  surface.      (Duret,)     The 
dotted  lines  indicate  the  territories  of  the  anterior,  middle  and  posterior  arteries. 

territory  of  the  third  convolution  (in  its  posterior  part).  I 
here  add  a  conclusively  corroborative  fact.  The  case  was 
a  woman  named  Farn ....  observed  at  Salpetriere.  She  was 
attacked  with  aphasia.  There  had  existed  no  trace  of  paral- 
ysis either  of  motion  or  sensation.  Aphasia  was  in  this  case 


54 


DISEASES   OF  THE   BRAIN. 


the  only  symptom,  and  atrophy  of  the  third  convolution  was 
also  the  only  corresponding  lesion  revealed  by  autopsy. 
(Figs.  13  and  14.)  This  is  incontestably  a  fine  example  of  cere- 
bral localization.1 

The  second  branch  of  the  Sylvian  is  the  anterior  parietal 
artery  of  Duret.  I  prefer  to  term  it  the  artery  of  the  ascend- 
ing frontal  convolution  (Fig.  9  and  Fig.  12). 


FIG.  13. — Human  brain,  anterior  lobe,  left  side.     (Life  size.) 

The  third  is  the  posterior  parietal  artery,  which  I  think 
would  be  better  named  artery  of  the  ascending  parietal  con- 
volution (Fig.  9  and  Fig.  12). 

The  fourth  branch  goes  to  the  gyrus  angularis  and  the  first 
sphenoidal  convolution  (Fig.  9  and  Fig.  12). 

1  We  published  the  complete  observations  of  that  case  in  Nos.  20  and  21  of  the 
Progres  Medical,  1874. 


ARTERIAL   CIRCULATION   IN  THE  BRAIN. 


55 


The  two  convolutions  to  which  the  second  and  third 
branches  of  the  Sylvian  artery  are  distributed  furnish,  accord- 
ing to  the  experiments  of  Ferrier  upon  the  monkey,  the  mo- 
tor centres  of  the  limbs.  You  see  that  from  the  arterial  dis- 
tribution these  two  convolutions  may  suffer  lesions  independ- 
ently of  each  other. 

I  do  not  know  if  the  complete  destruction  of  these  two 


FIG.  14. — Human  brain,  anterior  lobe,  right  side.     (Life  size.} 

central  convolutions  has  ever  been  seen,  but  here  is  a  case 
where  entire  destruction  occurred  of  the  ascending  parietal 
convolution,  which  in  the  monkey  is,  according  to  Ferrier, 
the  motor  centre  of  the  upper  limbs,  and  partially  so  of  the 
lower  ones. 

In  this  case  the  convolution  in  question  was  replaced  by  a 
depressed  yellow  spot.     The  frontal  ascending   convolution 


50  DISEASES   OF  THE  BRAIN. 

was  not  greatly  altered,  though  it  was  manifestly  atrophied. 
Now,  though  the  thalami  optici  and  the  corpora  striata  were 
in  that  case  uninjured  —  their  integrity  was  very  explicitly 
mentioned — there  existed  a  complete  and  permanent  hemi- 
plegia  in  the  upper  and  lower  limbs  of  the  opposite  side 
(Fig.  15). 


FIG.  15. — Human  brain,  left  side  ;  destruction  of  the  ascending  parietal  convolution 
and  a  great  part  of  the  frontal  ascending  convolution. 

This  is  a  result  which  contrasts  singularly  with  those 
accompanying  two  other  observations  relative  to  extended 
lesions  occupying  other  portions  of  the  gray  cortex  of  the 
brain.  In  one  case  of  limited  destruction  of  the  quadrilateral 
lobule  (yellow  spot)  there  was  no  corresponding  paralysis. 
In  another  case,  there  was  also  a  yellow  spot  which  included 
a  large  extent  of  the  inferior  face  of  the  sphenoidal  lobe, 
which  you  know  is  arterialized  by  the  posterior  cerebral 
artery.  Here,  also,  in  life  there  existed  not  a  trace  of 
hemiplegia. 

I  think  these  examples,  which  I  could  easily  multiply,  will 
suffice  to  convince  you  that  some  day  not  far  in  the  future,  it 
will  be  possible  to  surely  establish  in  the  human  subject  the 
doctrine  of  localization,  at  all  events  as  concerns  the  super- 
ficial parts  of  the  brain. 

After  the  description  which  I  have  given  respecting  the 
Sylvian  artery,  I  think  I  may  be  brief  in  that  concerning  the 


ARTERIAL   CIRCULATION   IN   THE   BRAIN. 


57 


subdivision  into  secondary  department  of  the  main  cortical 
vascular  territories  of  the    anterior   and    posterior   cerebral 

arteries. 

Fiss,  of  .Rolando 

„  cent,  cony. 
|Post.cettfc.cojiV. 

*£*> 

r*& 


FIG.  16. — Vascular  territories  of  the  internal  or  median  face  of  the  human  brain, 
indicated  by  the  dotted  lines. 

III.  The  anterior  cerebral  artery  is  much  less  frequently 
the  seat  of  serious  alterations  than  the  Sylvian.  That  fact  is 
doubtless  in  part  owing  to  the  angle  at  which  the  Sylvian 
leaves  the  internal  carotid  artery  (Figs.  12,  16,  and  17). 

This  artery  gives  three  principal  branches  :  the  first  nour- 
ishes the  two  inferior  frontal  convolutions  ;  the  second,  much 
more  important,  is  distributed  (less  commonly  than  the 
Sylvian,  but  much  oftener  than  the  anterior  cerebral)  to  the 
gyrus  fornicatus  (Fig.  16),  to  the  corpus  callosum,  to  the 
first  frontal  convolution  (internal  and  external  faces),  to  the 
paracentral  lobule  and  upon  the  convex  face  of  the  frontal 
lobe,  to  the  first  and  second  frontal  convolutions  (Fig.  17), 
and  finally  to  the  superior  extremity  of  the  ascending  frontal 
convolution.  The  third  branch  of  the  anterior  cerebral  artery 
is  sent  to  the  quadrilateral  lobule,  which  may  be  subject  to 
lesions  on  its  own  account,  as  I  have  just  now  given  you  an 
example. 


58  DISEASES   OF  THE   BRAIN. 

IV.  The  posterior  cerebral  artery  (Figs.  12,  16,  and  17) 
often  suffers  alterations  by  embolismus  and  thrombus. 

Ischaemic  softenings  of  the  posterior  lobes  are  much  more 
common  than  with  the  anterior  lobes. 

The  territory  of  this  artery  is  divided  into  three  secondary 


FIG.  17. — Vascular  territories  of  the  inferior  face  of  the  human  brain,  indicated  by 
the  dotted  lines. 

departments,  corresponding  to  three  arteries  of  the  second 
order.  The  first  of  these  goes  to  the  gyrus  angularis ;  the 
second  to  the  inferior  part  of  the  sphenoidal  lobe,  embracing 
the  inferior  sphenoidal  convolution  and  the  fusiform  lobule  ; 
the  third  goes  to  the  lingual  lobule,  to  the  cuneus,  and  the 
occipital  lobe  proper. 


SEVENTH   LECTURE. 

CIRCULATION  IN  THE  CENTRAL  MASSES  (GRAY  GANGLIA 
AND  THE  INTERNAL  CAPSULE). 

Summary :— Arterial  Circulation  in  the  Gray  Central  Ganglia ;  Intra- 
Enccplialic  Hemorrhage. — Anatomico-Pathological  Differences  be- 
tween the  Peripheral  and  Central  Parts  of  the  Brain. — Relative  In- 
frequency  of  Cerebral  Hemorrhage  in  the  Peripheral  Regions ;  its 
Frequency  in  the  Central  Parts. — Origin  of  the  Arteries  of  the  Cen- 
tra,! System. — Terminal  Arteries;  their  Characters. — Independence 
of  the  Cortical  and  Central  Arterial  Systems.— Analogies  between 
the  Arteries  of  the  Protuberance,  the  Bulb,  and  the  Central  Ganglia. 
—Their  Mode  of  Origin  Explains  the  Predominance  in  those  Parts  of 
Arterial  Ruptures.— Branches  Composing  that  System  rise  from  the 
Anterior  and  Posterior  Cerebral  Arteries  and  the  Sylvian  Artery. — 
Arrangement  of  the  Gray  Ganglia  ;  their  Form  and  Relations.— Con- 
siderations upon  the  Internal  Capsule  ;  its  Constituent  Parts  (Direct 
Peduncular  Fasciculi,  Indirect  Peduncular  Fasciculi,  Diverging 
Fasciculi). 

GENTLEMEN  : 

In  the  preceding  lecture  I  concluded  the  anatomico-medi- 
cal  description  of  the  cortical  arterial  system  of  the  brain. 
I  now  purpose  to  call  your  attention  to  the  arterial  circu- 
lation in  the  gray  central  ganglia.  Under  this  term  are 
included  the  thalami  optici,  the  corpora  striata,  and  their  so- 
called  appendages.  This  is  a  study  which  should  receive  our 
closest  care,  for  the  phenomena  which  result  from  vascular 
lesions  in  these  ganglia  are  clinically  of  no  less  importance 
than  those  which  come  from  alterations  in  the  arterial  system 
of  the  superficial  or  cortical  parts  of  the  hemispheres.  We 
will  find  in  these  central  parts  of  the  brain  ischaemic  altera- 
tions such  as  belong  to  its  superficial  layers  ;  but,  besides 
these,  we  will  there  find,  and  upon  a  larger  scale,  lesions  which 
are  rare  upon  the  periphery.  I  refer  to  common  intra-ence- 


60  DISEASES   OF  THE  BRAIN. 

phalic  hemorrhage,  one  of  the  most  constant  anatomical 
causes  of  those  symptoms  signified  by  the  term  apoplexy. 

In  this  connection  there  exists  a  difference  sufficiently  in- 
teresting to  be  noticed  between  the  peripheral  and  central 
parts  of  the  brain.  In  the  periphery,  intra-encephalic  hem- 
orrhage is  relatively  rare,  whereas  in  the  centre  it  is  common. 
This  is  a  fact  of  which  the  statistics  of  Andral  and  Durand- 
Fardel  are  eloquent  witnesses,  and  they  are  confirmed  by 
recent  statistics.  Thus,  of  119  cases  collected  by  Andral 
and  Durand-Fardel,  the  thalami  optici  and  corpora  striata 
have  been  found  the  original  seat  of  hemorrhage  in  102 
cases  ;  in  only  17  cases  has  the  hemorrhagic  origin  been  either 
in  the  anterior  or  posterior  lobe  or  at  the  periphery  of  the 
brain.  On  the  other  hand,  ischaemic  softenings  of  the  brain 
predominate,  as  Durand-Fardel  truly  says,  in  the  periphery. 
The  facts  which  I  have  gathered  at  Salpetriere  in  every  point 
confirm  these  statements. 

We  will  presently  indicate  some  of  the  conditions  necessary 
to  explain  this  remarkable  contrast ;  just  now  it  is  sufficient 
to  convince  you  that  our  review  of  the  corticular  arterial 
system  was  a  necessary  introduction  to  the  chapter  upon 
ischaemic  softenings  of  the  brain  ;  the  studies  which  will  oc- 
cupy us  to-day  furnish  the  obligatory  preface  of  the  equally 
interesting  history  of  intra-encephalic  hemorrhage. 

I.  You  remember  how  the  arterioles  of  the  central  system 
are  derived  from  the  three  great  arterial  trunks  of  the  brain, 
near  their  origin  in  the  circle  of  Willis.  The  arteries  which 
form  the  central  system  are  generally  vessels  of  some  size. 
For  the  corpora  striata  they  are,  according  to  Duret,  arteri- 
oles measuring  in  diameter  from  a  half  to  one  and  a  half 
millimetres. 

Their  mode  of  origin  calls  to  mind  the  shoots  rising  from 
the  base  of  forest  trees.  I  borrow  the  comparison  from 
Heubner,  which,  beyond  its  picturesque  character,  is  quite 
true  ;  only  it  must  not  be  carried  too  far,  for  the  arteries  of 
the  central  system,  at  their  point  of  departure,  take  a  direc- 
tion perpendicular  to  the  principal  trunk. 


CIRCULATION   IN   THE   CENTRAL   MASSES.  6l 

This  perpendicular  direction  brings  to  mind  that  which  we 
have  noticed  respecting  the  nutrient  arteries  of  the  cortex. 
But  it  is  well  not  to  forget  that  there  is  a  difference  between 
the  nutrient  cortical  vessels  and  the  arteries  of  the  gray  cen- 
tral ganglia ;  the  first,  indeed,  are  but  capillaries — at  least  as 
defined  by  Robin — and  the  second,  on  the  contrary,  are  ves- 
sels of  larger  size. 

Another  character  belonging  to  the  arteries  of  the  central 
ganglia  is  that  (as  the  term  is  used  by  Cohnheim)  they  are 
terminal  arteries  par  excellence.  If  the  independency  of  the 
vascular  territories  of  the  cortex  is,  as  we  have  seen,  open 
to  discussion,  it  is  not  the  same  respecting  the  central  arteries. 
Authors  fully  agree  that  they  are  entirely  independent  of 
each  other. 

Thus  Heubner  says  that  by  the  aid  of  a  Pravaz  syringe 
(its  point  blunted)  one  can  inject  each  of  the  small  arteries 
that  lead  to  the  various  parts  of  the  corpora  striata  and 
thalami  optici.  With  all  possible  precautions,  however,  one 
can  never  inject  the  entire  body  of  the  thalamus  opticus  or 
corpus  striatum.  Only  small  departments  of  each  can  be 
injected,  and  if  the  injection  is  made  too  forcibly,  ruptures 
are  produced  ;  but  notwithstanding  that,  the  vascular  territo- 
ries keep  to  their  assigned  limits. 

The  multiplied  experiences  of  Duret  are  to  the  same  effect. 
It  should  be  added  that  under  no  circumstances  can  an  injec- 
tion be  passed  by  way  of  the  central  arteries  into  the  domain  of 
the  cortical  arteries,  and  the  reverse  is  equally  true — the  cen- 
tral system  cannot  be  injected  through  the  cortical. 

It  is  perhaps  not  without  interest  to  notice  the  analogies  in 
the  manner  in  which  the  nutrient  arteries  originate  in  the  basi- 
lar  parts  of  the  encephalon,  in  the  protuberance,  and  even  in 
the  bulb. 

In  the  protuberance  the  resemblance  is  striking;  the  me- 
dian arteries  leave  the  voluminous  basilar  artery  at  right 
angles  and  penetrate  to  the  posterior  part  of  the  protuberance 
parallel  to  each  other  and  without  anastomosing,  reproduc- 
ing somewhat  the  type  of  terminal  arteries. 

In  the  bulb  the  same  method  exists,  but  somewhat  differ- 


62  DISEASES   OF  THE   BRAIN. 

ing  through  a  special  modification.  The  median  arteries  of 
the  bulb  do  not  rise  immediately  from  the  great  trunks  of 
the  vertebral  arteries  ;  they  have  their  origin  in  the  spinal 
arteries. 

This  mode  of  origin  and  distribution  of  the  arteries  of  the 
protuberance  and  the  central  ganglia,  possibly  explains  one 
of  the  reasons  (a  mechanical  one)  of  the  predominance  in 
those  parts  of  arterial  rupture. 

Remember  that  at  the  surface  of  the  brain,  where,  as  I 
have  said,  hemorrhages  are  comparatively  rare,  the  arteries 
are  not  admitted  to  the  pulp  except  after  a  long  journey 
through  the  pia  mater,  and  after  being  transformed  into  very 
slender  vessels,  in  fact  capillaries — recall,  I  say,  these  peculiari- 
ties, and  you  will  much  more  easily  comprehend  the  differences 
which  I  have  pointed  out  to  you  concerning  the  central 
arteries. 

1st.  The  distance  from  the  heart  to  the  large  ganglia  of  the 
base  is  very  short.  The  arteries  supplying  these  ganglia 
come  directly  from  the  arteries  forming  the  circle  of  Willis, 
that  is,  from  arteries  of  the  third  order  from  the  heart.  This 
is  evidently  favorable  to  arterial  ruptures.  To  be  sure,  this 
is  obviated  to  a  certain  degree  by  the  right  angle  at  the  ori- 
gin of  the  vessels,  and  also  by  a  considerable  reduction  of 
calibre. 

2d.  Compared  with  the  cortical  arteries,  the  central  are 
voluminous ;  I  allude  especially  to  the  arteries  of  the  corpora 
striata,  which  have  a  diameter  of  one-half  to  one  and  a  half 
millimetres. 

3d.  I  would  add  that  the  absence  of  anastomosis  seems  an 
unfortunate  condition,  for  in  case  of  increased  pressure  in  a 
vessel,  the  clearing  of  the  way  is  impossible  on  account  of 
the  absence  of  well-established  collaterals. 

The  three  great  arterial  trunks  of  the  brain  all  take  part  in 
the  vascularization  of  the  central  regions,  but  that  participa- 
tion is  very  unequal.  The  anterior  cerebral,  for  example, 
sends  only  a  few  vessels  to  the  head  of  the  corpus  striatum, 
and  even  these  inconstantly.  The  posterior  cerebral  artery 
has  a  domain  much  more  vast  and  important.  It  supplies 


CIRCULATION   IN  THE   CENTRAL  MASSES.  63 

the  thalami  optici,  and  to  a  great  extent  the  superior  portion 
of  the  crura  cerebri  and  the  tubercula  quadrigemina.  But 
here,  as  in  the  cortical  system,  the  Sylvian  arteries  incontesta- 
bly  play  the  preponderating  role.  These  arteries  furnish  all 
the  branches  which  go  to  the  caudated  ganglion  (with  the 
exception  of  a  little  field  of  variable  branches  from  the  ante- 
rior cerebral)  and  to  the  various  segments  of  the  lenticular 
ganglion. 

We  will  consequently  take  the  branches  of  the  Sylvian  ar- 
tery for  the  type  of  our  description.  After  that,  it  will  be 
easy  to  complete  the  description  of  the  central  nutrient  sys- 
tem with  the  addition  of  a  few  words  concerning  some 
branches,  derived,  as  may  chance,  from  either  the  anterior 
or  posterior  cerebral  arteries. 

II.  But  before  entering  into  the  detailed  description  of 
these  vessels  it  is  very  necessary  to  examine  more  closely 
than  we  have  hitherto  done  the  parts  to  which  they  are  dis- 
tributed. In  the  preceding  description  we  have  done  little 
else  than  to  name  the  parts,  and  in  a  summary  manner  to 
indicate  their  general  configuration.  That  rapid  notice  is 
insufficient.  We  must  enter  into  such  examinations  as  are 
necessary  to  the  acquisition  of  a  thorough  anatomical  knowl- 
edge. 

I  need  not  repeat  that  it  relates  to  those  parts  so  interesting 
as  concerns  the  theory  of  cerebral  localizations,  namely,  the 
thalami  optici,  the  caudated  ganglion,  the  lenticular  ganglion, 
and  the  internal  capsule.  Such  are  the  various  constituents 
which  united  form  that  which  is  called  the  central  system,  in 
distinction  from  the  cortical  system. 

Bring  to  mind  how  the  crura  cerebri,  rounded  at  the  point 
where  they  border  the  thalami  optici,  flatten  after  having 
passed  it,  internally  and  externally  spreading  forward  and 
backward  like  a  fan.  Upon  that  fan — allow  me  to  continue 
the  simile — the  ganglia  of  the  gray  substance  are  arranged  as 
follows  :  the  thalami  optici  within  and  posteriorly ;  within, 
but  before  and  above,  the  caudated  ganglion  ;  outside  of  the 
fan,  and  below  the  thalami  optici  and  caudated  ganglion,  is 


64  DISEASES   OF  THE   BRAIN. 

situated  the  lenticular  ganglion,  which  extends  nearly  as  far 
forward  as  the  head  of  the  corpus  striatum,  and  backward 
nearly  as  far  as  the  posterior  extremity  of  the  thalami  optici. 

I  only  wish  to  indicate,  en  passant,  the  forms  and  principal 
relations  of  the  gray  ganglia  which  I  have  enumerated. 

I st.  The  thalamus  opticus  has  a  flattened,  ovoid  appearance. 
The  superior  face  looks  upon  the  lateral  ventricle,  and  the  in- 
ferior, which  is  also  the  internal,  upon  the  middle  ventricle. 
On  dissection  it  is  with  difficulty  separated,  on  account  of  its 
numerous  and  close  connections  with  contiguous  parts. 

2d.  The  caudated  ganglion  has  the  form  of  a  comma  —  or 
of  a  pyramid  —  the  large  end  'of  which  is  directed  forward 
and  inward,  the  small  end  upward  and  outward.  Its  su- 
perior face  protrudes  into  the  ventricle  ;  the  so-called  internal 
face  is  mostly  in  contact  with  the  superior  portion  of  the  in- 
ternal capsule.  This  ganglion  is  very  easily  detached  in 
dissections,  but  in  order  to  isolate  it,  the  numerous  fasciculi 
which  it  receives  from  the  internal  capsule  must  be  broken. 

3d.  The  lenticular  ganglion,  although  all  its  surface  is  cov- 
ered, can  easily  and  without  much  art  be  isolated  from  the 
neighboring  parts.  Its  general  form  is  ovoid,  with  an  an- 
terior and  a  posterior  extremity.  There  can  be  distinguished 
in  it  two  parts  :  (a)  The  anterior  third,  more  obtuse,  and  com- 
posed of  a  uniform  mass  of  gray  substance,  is,  at  its  very  an- 
terior extremity,  confounded  with  the  intraventricular  nu- 
cleus of  the  corpus  striatum.  (b)  The  second  portion,  the 
posterior  two-thirds  of  the  lenticular  ganglion,  is  flattened 
from  above  downward  in  such  wise  as  to  offer  an  angle 
turned  inward  towards  the  internal  capsule.  The  internal 
and  superior  face  is  intimately  united  to  the  internal  capsule, 
and  the  inferior  face  is  parallel  with  the  base  of  the  brain. 
The  external  face  is  in  rapport  with  the  external  capsule,  and 
its  intermediate  with  the  front  wall  of  the  island  of  Reil. 
The  island  lies  close  to  it  in  its  entire  extent.  An  interesting 
preparation  consists  in  carefully  removing  successively  the 
gray  substance  of  the  convolutions  of  the  island,  the  anterior 
wall,  and  the  external  capsule,  which  lays  bare  the  external 
face  of  the  lenticular  ganglion. 


CIRCULATION   IN   THE   CENTRAL   MASSES.  65 

In  hardened  specimens  the  separation  between  the  external 
face  of  the  lenticular  ganglion  and  the  external  capsule  is 
effected  without  art  and  with  the  utmost  ease.  This  is  be- 
cause there  are  no  medullary  fasciculi  —  and  you  see  that 
there  are  no  vessels — which  bind  the  external  capsule  to  the 
third  segment  of  the  lenticular  ganglion. 

From  the  connections  which  we  have  outlined  it  might  be 
said  that  the  three  ganglia  or  gray  central  masses — thalamus 
opticus,  caudated  ganglion,  and  lenticular  ganglion — are  in 
some  sense,  as  Foville  has  said,  appendices  to  the  internal 
capsule,  like  cotyledonal  prolongations  of  the  crura  cere- 
bri. 

On  the  side  of  the  ventricles  the  thalami  optici  and  the 
caudated  ganglia  are  isolated  ;  the  lenticular  ganglion  is  also 
isolated,  virtually,  at  least,  on  the  side  of  the  island.  These 
gray  ganglia,  then,  form  a  distinct  system  from  the  other  parts 
of  the  brain,  as  well  by  their  connections  as  by  their  mode 
of  vascularization. 

Vertical  sections  will  enable  you  to  easily  understand  the 
relations  of  the  central  parts.  I  will  not  at  this  point  dwell 
upon  the  structural  details  of  the  different  ganglia,  but  will 
return  to  them  as  occasion  requires.  Some  examination  and 
idea  of  the  construction  of  the  internal  capsule,  however,  is 
indispensable. 

The  internal  capsule,  in  part  at  least,  is  the  prolongation, 
not  of  the  entire  crus  cerebri,  but  of  the  foot  or  crusta,  the 
inferior  part  only.  The  tegmentum  or  superior  part,  which 
is  separated  from  the  foot  by  the  locus  niger,  enters  into  rela- 
tions especially  with  the  tubercula  quadrigemina  and  the 
thalami  optici  ;  it  takes  no  direct  part  in  the  formation  of  the 
internal  capsule. 

An  old  opinion  held  the  internal  capsule  as  a  complete  and 
immediate  emanation  from  the  foot  of  the  diverging  fibres. 
This  is  an  error  which  Luys  and  Kolliker  have  corrected. 
These  authors  have,  in  fact,  demonstrated  that  the  fibres  com- 
ing from  the  peduncle  stop  by  the  way  to  enter  various 
ganglia.  I  think,  however,  they  have  gone  too  far,  in  holding 
that  the  internal  capsule  is  entirely  formed,  ist,  of  diverging 
5 


66  DISEASES   OF   THE   BRAIN. 

fibres  which   terminate   in  the   ganglia  ;    2<d,  of  fibres  which 
leave  the  ganglia  and  become  diverging  fibres. 

From  very  delicate  anatomical  observations,  Meynert, 
Henle,  and  Broadbent  have  expressed  the  opinion  that  there 
exists  a  third  order  of  fibres  which  communicates  directly 
from  the  foot  of  the  peduncle  to  the  gray  cortex. 

The  verification  of  the  existence  of  these  last  fasciculi  de- 
pends, as  you  will  see,  upon  certain  pathological  proofs.  I 
will  cite,  among  others,  some  cases  of  descending  degenera- 
tions observed  by  Vulpian  and  myself.  In  the  cases  referred 
to,  destruction  and  yellow  spots  had  largely  invaded  the 
median  convolutions,  without  concomitant  alterations  of  the 
corpora  striata,  and  had  produced  progressive  degeneration, 
which  could  be  followed  across  the  isthmus  and  to  the  lower 
region  of  the  spinal  cord.  We  are  indebted  to  Gudden  for  a 
series  of  experiments  which  I  will  later  have  occasion  to 
notice,  and  the  results  of  which  have  the  same  bearing. 

Henle l  goes  too  far,  perhaps,  when  he  writes  in  his  de- 
scription of  the  nervous  system  that  the  internal  capsule  is 
composed  entirely  of  the  fibres  from  the  foot  of  the  peduncle. 
Certainly — and  we  will  have  occasion  to  return  to  this  sub- 
ject— both  pathological  and  experimental  facts  in  favor  of  the 
existence  of  these  fibres  are  numerous  and  important,  and 
the  facts  permit  a  belief  (we  will  further  on  see  the  demon- 
stration), that  among  the  direct  fibres  some  (the  anterior)  are 
centrifugal  and  connected  with  movements  of  the  limbs, 
while  others  (the  posterior)  are  centripetal  and  connected 
with  the  transmission  of  sensorial  impressions  (Fig.  18). 

To  sum  up,  the  internal  capsule,  according  to  modern  re- 
searches,2 is  composed  as  follows  : 

ist.  By  the  direct  peduncular  fasciculi,  which  traverse  the 
capsule  without  entering  the  ganglia. 

2d.  By  the  indirect  peduncular  fasciculi.  Of  these  some 
are  sent  to  the  corpora  striata,  which  they  approach  by  the 
inferior  face  ;  others  go  to  the  lenticular  ganglia,  which  they 

1  Henle. — Nervenlehre,  p.  261. 

9  Huguenin. — Allg.  Patholog.  der  Krankh.  des  Nervensystems ;  Zurich,  1873, 
p.  94,  Fig.  70;  p.  85,  Fig.  63  ;  p.  119,  Fig.  82  ;  p.  127. 


CIRCULATION  IN   THE   CENTRAL  MASSES.  6/ 

penetrate  by  its  first  segment.     Very  numerous  in  this  seg- 
ment, they  become  less  and  less  in  the  second  and  third  seg- 


Flbers  of  optic  thalamus 
extending  to  the  periphery 

Caudated  nucleus 


Kbers  of  caudated  nucleus 
extending  to\the  periphery 


Jhrecb 
fibers. 


FIG.  18. — Scheme  illustrative  of   the   different  orders  of   peduncular  fibres. — 
Huguenin. 

ments,  and  to  that  unequal  distribution  is  due  the  difference 
in  color  of  the  three  segments  of  the  lenticular  ganglion. 


68 


DISEASES   OF   THE   BRAIN. 


There  is  no  question  as  to  whether  the  fibres  from  the  foot 
of  the  peduncle  go  to  the  thalami  optici ;  the  thalami  optici 
receive  no  other  fasciculi  from  the  cerebral  peduncles  except 
those  from  the  tegmentum. 

To  the  fasciculi  which  go  from  the  foot  of  the  peduncle  to 


Piters  from  the  2  Int.  Segments  of  lent,  nucleus, 

Caudated  nucleus/ 
External  portion  of  optic  thalamiii/ 
Int. portion  of  opti 


Fibers  from  Che 
\  tapetum. 


\    /Int.Cap^ue,'    ^?^          ^Anterior  corrimbsure 
X..,  \    J       '^'lenticular  nucleus. 

&  Optic  ganglion .       yjasilar  portion 

Dlcaudatecl  nucleus. 

<|f  Three  layers  of  unnamed  sub  stance. 
FIG.  19. — Section  of  lenticular  ganglion  and  its  surroundings. — (Ifeynert.) 

the  gray  central  ganglia  are  added,  in  the  superior  part  of 
the  internal  capsule,  fasciculi  which  originate  in  the  gray 
ganglia,  and  go  towards  forming  the  diverging  fibres  that 
run  to  the  gray  layer  of  the  cortex.  These  fasciculi  bear  the 
name  of  radiating  fasciculi  (StabkranzbUndet).  There  can  be 
distinguished,  1st,  the  diverging  fasciculi  of  the  corpora  stri- 
ata  ;  2d,  the  radiating  fasciculi  of  the  thalami  optici ;  3d,  the 
radiating  fasciculi  issuing  from  the  lenticular  ganglion,  which 
come  principally  from  the  superior  border  of  the  second  and 
third  segments. 


CIRCULATION   IN  THE   CENTRAL   MASSES.  69 

It  follows  from  this  exhibit  that  four  orders  of  fasciculi  enter 
into  the  composition  of  the  diverging  fibres,  and  so  attach  the 
internal  capsule  to  the  cortex  of  the  convolution. 

They  are  :  1st,  the  radiating  fasciculi  of  the  thalami  optici ; 
2d,  those  of  the  corpora  striata  ;  3d,  those  of  the  lenticular 
ganglion — these  various  fasciculi  attach  the  gray  central  gan- 
glia to  the  cortex  ;  4th,  the  direct  fasciculi  which  go  from  the 
foot  of  the  peduncle  to  the  gray  cortex  without  stopping  in 
the  gray  central  ganglia. 

In  the  internal  capsule  itself,  and  also  in  the  foot  of  the 
diverging  fibres,  one  can  recognize  these  various  modes  of 
origin  by  submitting  thin  slices,  properly  hardened,  to  a  low 
power  of  the  microscope  ;  to  be  sure,  the  research  is  not  ex- 
empt from  difficulty.  A  little  above  that  point,  however,  all 
the  fasciculi  intermix  in  the  most  varied  manner,  either  among 
themselves,  or  it  may  be  with  the  commissural  fibres,  in  such 
manner  as  to  form  an  inextricable  net-work,  called  the  central 
white  substance.  We  will  soon  render  an  exact  account  of 
the  interest  pertaining  to  this  arrangement. 


EIGHTH   AND   NINTH    LECTURES. 

CENTRAL  ARTERIES.— ISOLATED    LESIONS   OF   THE   GRAY 

GANGLIA. 

Summary  :— Origin  of  the  Arterial  System  of  tlie  Central  Ganglionic 
Masses.— Unequal  Participation  of  the  Main  Arteries  of  the  Brain 
Constituting  this  System.— Description  of  the  Striated  Arteries;  In- 
ternal Striated  Arteries;  External  Striated  Arteries  (Lenticnlo-Stri- 
ated,  Lenticulo-Optic). — Terminal  Arteries. — Consequences  of  Obliter- 
ations of  Central  Arteries  Emanating  from  the  Sylvian  Artery.— Soft- 
ening of  the  Optico-Striated  Bodies. — Intra-Encephalic  Hemor- 
rhage.—Regional  Diagnosis.— Isolated  Lesions  of  the  Gray  Ganglia 
without  Participation  of  the  Internal  Capsule.— Cerebral  Hemi- 
plegia,  Central  and  Cortical.— Lesions  of  the  Internal  Capsule.— 
"Variations  of  Symptoms  according  to  the  Spot  in  the  Internal  Cap- 
sule Occupied  by  the  Lesions. — JYew  Anatomical  Considerations  :  Pe- 
duncular Fibres  going  Directly  to  the  Cortical  Substance  of  the 
Occipital  Lobe  ;  their  Role  Relative  to  Sensibility.— Proofs  Fur- 
nished, 1st,  by  Lesions  of  the  Posterior  Lenticulo-Optic  Regions 
of  the  Internal  Capsule  (Hemi.Anaesthesia  Cerebral);  3d,  by  Ex- 
perimentation. 

GENTLEMEN  : 

I.  You  remember  that  the  three  great  arteries  of  the  brain 
take  an  unequal  part  in  forming  the  arterial  system  of  the 
central  ganglionic  masses. 

A. — (a.)  Thus,  the  Sylvian  artery  very  greatly  predomi- 
nates. It  furnishes  :  1st,  in  great  part,  the  caudated ganglion  ; 
2d,  the  entire  lenticular  ganglion  ;  $d,  a  portion  of  the  thala- 
mus  options  ;  4th,  the  whole  extent  of  the  internal  capsule. 

(#.)  The  anterior  cerebral  artery  has,  on  the  contrary,  very 
modest  attributes.  It  arterializes  only  the  head  of  the  cau- 
dated ganglion,  and  even  in  this  its  participation  is  not  con- 
stant. 

(c.)  As  for  the  posterior  cerebral  artery,  its  role  is  more 


CENTRAL   ARTERIES. 


important  and  tolerably  characteristic.  That  artery,  which  is 
extensively  distributed  (as  it  sends  branches  to  the  choroid 
plexuses,  to  the  ventricular  walls,  etc,),  furnishes  the  following 
regions  of  the  central  masses  :  1st,  the  external  and  posterior 
part  of  the  thalami  optici  ;  2d,  the  tubercula  quadrigemina ; 
3d,  the  superior  portions  of  the  crura  cerebri. 

, Section  of  lafc. ventricle. 

/ftigone  pillar 

'Caudated  nudeua* 


Ont .  carjdt .  artery,  (L  entinudeus  of  cojp  .strialunid 

lvian  dfay.j  tExt.capsule. 

r 


Int. arteries  , 
of  corpus  stratum. 

Qiiasma  of  optic  nervejsj.     j 

Grey  substance  of  3 -ventridf      [Section  of  optic  Land. 
FlG.  20. — Transverse  section  of  the  cerebral  hemispheres,  one  centimetre  posterior 
to  the  optic  chiasma.     Arteries  of  the  corpora  striata. — (Duret.)     Vascular  territories 
indicated  by  dotted  lines. 

The  plates  (Figs.  20  and  21),  on  which  the  vascular  ter- 
ritories are  separated  by  dotted  lines,  will  make  the  details 
clearer. 

The  description  of  the  striated  arteries  alone  requires  some 
explanation.  With  this  you  will  possess,  in  brief,  all  that  is 
necessary  to  a  knowledge  of  the  central  arteries,  whether  they 
come  from  the  anterior  or  the  posterior  cerebral  arteries. 

Emanating  from  the  superior  border  of  the  Sylvian  artery, 
the  striated  arteries  enter  the  apertures  of  the  anterior  per- 
forated space,  where  they  soon  disappear  from  sight.  But  a 
very  simple  preparation  renders  it  possible  to  follow  them  in 
the  first  part  of  their  intracerebral  course.  I  solicit  attention 
to  the  following  description,  because  that,  in  order  to  under- 


72  DISEASES   OF   THE   BRAIN. 

stand  some  important  facts,  it  is  indispensable   to   know  the 
theory  of  common  cerebral  hemorrhage. 

That  exposition  consists  in  destroying  successively  the 
gray  cortex  of  the  island  of  Reil,  the  subjacent  white  sub- 
stance, the  anterior  wall,  and  finally  the  internal  capsule. 


Lenticular  ftud 

Bora  of  .Anuiion 


Sfhenoidal  Horn 
oCUUfentridA 


Post,  cerebral  Arteries 


FIG.  21. — Vertico-transverse  section  of  the  human  brain,  posterior  to  the  tuber- 
cula  mammillaria  and  anterior  to  the  peduncles.  Vascular  territories  indicated  by 
dotted  lines. 

Thus  the  entire  external  surface  of  the  lenticular  ganglion  is 
laid  bare.  If  the  preparation  has  been  somewhat  carefully 
made,  upon  a  well-injected  brain — and  the  preparation  is 
easily  made,  because,  in  its  anterior  part  at  least,  the  lenticu- 
lar ganglion  is  as  it  were  naturally  detached  from  the  internal 
capsule — one  can  follow  the  first  part  of  the  distribution  of 


CENTRAL   ARTERIES.  73 

the  principal  striated  arteries.  By  this  artifice  it  is  seen  that 
they  spread  like  a  fan  at  the  surface  of  the  gray  ganglia.  But 
at  a  short  distance  from  their  origin  they  bury  themselves  in 
the  substance  of  the  third  segment,  where  they  disappear. 

Now,  it  is  upon  the  transverse  sections  that  one  must  fol- 
low the  ulterior  distribution  of  the  striated  arteries. 

A  first  section,  made  behind  the  chiasma  (Fig.  20),  shows 
only  the  caudated  and  lenticular  ganglia,  the  thalami  optici 
being  more  posterior.  Upon  that  section  are  found  the 
deepest  tracts  of  the  arteries  which  we  have  just  had  under 
observation.  Besides  these,  other  and  smaller  arterioles  may 
be  discovered  on  the  external  surface  of  the  lenticular  ganglia, 
and  which  may  be  termed  internal ;  after  detaching  them- 
selves from  the  Sylvian  trunk,  they  rise  nearly  perpendicularly 
into  the  first  two  segments  of  the  lenticular  ganglion  and  the 
adjoining  parts  of  the  internal  capsule. 

Of  still  greater  interest  are  the  external  striated  arteries, 
those  which,  in  the  first  part  of  their  course,  run  over  the 
external  face  of  the  lenticular  ganglia.  They  should  be 
divided  into  two  groups  :  the  first  group  is  anterior,  and  the 
arteries  of  which  it  is  composed  are  the  I enticulo- striated 
arteries  ;  the  second  group  is  posterior,  and  the  arteries  which 
constitute  it  are  the  lenticulo-optic  arteries. 

One  of  the  arteries  in  the  anterior  group  is  especially 
important  on  account  of  its  size  and  its  predominant  role 
in  intra-encephalic  hemorrhage  ;  it  could  be  appropriately 
called  the  artery  of  cerebral  hemorrhage.  After  having  en- 
tered the  third  segment  it  traverses  the  superior  portion  of  the 
internal  capsule,  then  enters  the  body  of  the  caudated  ganglion. 
It  then  continues  from  behind  forward  to  the  most  anterior 
part  of  that  ganglion. 

The  distribution  of  this  striated  artery,  as  well  as  that  of 
the  lenticulo-striated  arteries,  should  be  studied  from  sections 
made  anterior  to  the  one  which  has  thus  far  served  us. 

The  lenticulo-optic  arteries  are  after  the  same  model,  only 
after  having  traversed  the  most  posterior  part  of  the  internal 
capsule,  they  encounter  the  external  and  anterior  part  of  the 
thalamus  opticus,  over  which  they  spread. 


74  DISEASES   OF   THE  BRAIN. 

I  would  remind  you  that  we  are  dealing  with  terminal 
arteries,  and  that  if  the  injections  are  too  strongly  pressed 
they  will  produce  little  ruptures  upon  different  points  of  the 
vascular  tract,  thus  imitating  in  locality,  as  well  as  in  form, 
the  centres  of  hemorrhage  which  are  produced  pathologically. 

About  the  branches  of  the  anterior  cerebral  artery,  we 
have  nothing  especial  to  say,  except  that  they  do  not  con- 
stantly exist,  and  that  they  give  place  to  very  circumscribed 
hemorrhages,  though  really  grave,  inasmuch  as  they  often 
open  into  the  ventricles. 

As  for  the  posterior  cerebral  artery,  I  repeat  that  it  merits 
by  itself  more  minute  attention.  I  only  wish  to  notice  here 
the  arteries  which  it  sends  to  the  thalami  optici. 

These  arteries  are  of  two  orders  :  1st,  the  posterior  internal 
optic  artery,  arising  from  the  posterior  cerebral  near  its  origin 
at  the  basilar  trunk,  and  which  furnishes  the  internal  face  of 
the  thalamus  opticus,  and  is  capable  in  its  ulterior  tracts  of 
occasioning  hemorrhages,  of  small  extent  to  be  sure,  but 
serious,  as  being  often  followed  by  ventricular  inundation  ; 
2d,  the  posterior  external  optic  artery,  which  comes  from  the 
posterior  cerebral  after  it  has  passed  around  the  crus  cerebri, 
and  in  which  it  ascends  obliquely  before  entering  the  posterior 
part  of  the  thalamus  opticus.  The  rupture  of  this  vessel 
produces  hemorrhage  which  often  breaks  into  the  body  of  the 
crura  cerebri.  This  artery  deserves  your  close  attention,  for, 
as  you  will  see  later,  lesions  within  its  territory  produce  a 
train  of  symptoms  altogether  peculiar  to  themselves. 

II.  In  journeying  along  we  have  gathered  facts  in  the 
highest  degree  interesting  for  the  theory  of  cerebral  patho- 
logical localizations,  and  we  will  now  examine  these  facts  more 
closely,  commencing  with  those  which  concern  the  central 
ganglionic  masses. 

A.  (a.)  The  entire  system  of  the  central  arteries  emanating 
from  the  Sylvian,  may  be  obliterated  in  consequence  of  a 
thrombus  or  an  embolus  of  the  principal  arterial  trunk. 
Then  follows  softening  of  nearly  the  entire  mass  of  the  gray 
ganglia,  the  district  corresponding  to  the  anterior  cerebral 


CENTRAL  ARTERIES.  75 

and  the  posterior  optic  arteries  alone  being  spared.  Here  is 
a  very  concise  localization,  generally  of  an  extreme  gravity, 
and  which  embraces,  clinically  speaking,  all  the  pathology  of 
the  ganglionic  centres.  The  symptoms  which  belong  to  a 
softening  of  the  entire  optico-striated  bodies  (the  entire  cen- 
tral masses  are  sometimes  so  called)  are  none  other  than 
common  cerebral  hemiplegia  accompanied  with  cerebral  hemi- 
ancesthesia. 

(b.)  Analysis  may  be  brought  to  bear  on  this  complex 
whole.  We  must  not  believe,  however,  that  we  are  at  present 
able  to  recognize  the  special  symptoms  which  belong  to  the 
destruction  of  the  thalami  optici,  the  caudated  ganglia,  or  the 
lenticular  ganglia,  and  still  less  to  the  various  segments. 

(V.)  It  is  possible,  however,  by  reason  of  the  arterial  distribu- 
tion which  we  have  described,  that  the  anatomical  locality 
may  betray  itself  by  special  symptoms,  thus  affording  a  re- 
gional diagnosis.  This  is  realized  when  the  softening  affects 
all,  or  nearly  all,  of  the  territory  of  the  lenticulo-striated  arteries, 
or  that  of  the  lenticulo-optic  arteries.  The  two  different  events 
differ  in  their  symptoms  ;  the  symptoms  of  hemianaesthesia  are 
present  when  the  field  of  the  lenticulo-optic  arteries  is  invaded, 
and  absent  when  the  lenticulo-striated  arteries  are  the  ones 
involved. 

B.  That  which  has  been  said  relative  to  ischaemic  softening 
is  also  applicable  to  intra-encephalic  hemorrhage.  This,  you 
know,  is  frequent,  and  especially  in  these  regions  ;  the  striated 
arteries  are,  indeed,  very  prone  to  a  special  form  of  arterial 
sclerosis  which  produces  miliary  aneurisms.  One  often  ex- 
tracts from  a  recent  hemorrhagic  centre  a  striate  or  an  optic 
artery,  the  prolongations  of  which  have  small  aneurisms.1 

Contrary  to  current  opinion,  sanguineous  effusion  gener- 
ally occurs  (as  Gendrin  has  long  since  recognized2),  in  such 
cases,  not  at  first  in  the  body  of  the  corpus  striatum  it- 
self, but  outside  of  it — to  be  more  exact,  in  contact  with  the 
external  surface  of  the  lenticular  ganglion,  between  that  and 

1  See  plate  V.  of  Archives  de  physiologie,  1868. 

2  A.  N.  Gendrin,  Traite  philosophique  de  medecine  pratique,  t.  I.,  1838.     See 
page  443,  Nos.  789,  796;  p.  465,  Nos.  808,  809,  810;  and  page  478,  No.  830. 


70  DISEASES   OF   THE   BRAIN. 

the  external  capsule,  which  becomes  detached.  Thus  are 
produced  those  flat  centres  which  upon  transverse  sections 
appear  like  narrow  linear  lacunae,  nearly  vertical,  and  parallel 
to  the  gray  ganglion  of  the  front  wall  (Fig.  22).  When  the 
sanguineous  effusion  is  abundant  the  hemorrhagic  centre 
extends,  especially  transversely,  and  on  account  of  the  greater 
resistance  of  the  cranial  walls  and  the  wall  of  the  island,  the 
central  masses,  enucleated  so  to  speak,  are  crowded  back  en 
bloc  towards  the  ventricular  cavity  (Fig.  22). 


L  ateral  Ventricle 


norragic  center    / 

destroying  ext .  capsule; 

L  enticulo  -  strata  '-portion  .of  int.  capsule* 

FIG.  22. — Extra-lenticular  hemorrhagic  centre,  posterior  to  the  optic  chiasma. 
{  No  hem  iancesthesia . ) 

I  have  given  very  ordinary  cases,  but  it  may  happen  also 
that  extravasation  coming  from  the  extremities  of  the  termi- 
nal arteries  will  occur  in  the  body  even  of  either  the  corpus 
striatum  or  of  the  thalamus  opticus. 

Be  that  as  it  may,  the  only  clinical  localization  possible  in 
these  cases  is,  as  in  case  of  softening,  those  which  corre- 
spond to  the  lenticulo-striated  or  the  lenticulo-optic  domains. 

The  symptoms  of  hemorrhage  are  at  present  more  difficult 
of  interpretation  or  of  exact  localizing  than  are  those  of 
softening.  Uninformed,  one  would  be  liable  to  attribute 


CENTRAL   ARTERIES.  77 

certain  symptoms  to  the  destruction  of  a  part  which  really 
was  only  the  result  of  a  neighboring  accident.  I  allude  to 
compression,  which,  during  effusion,  however  slight  it  may  be, 
never  fails  to  somewhat  affect  the  adjacent  parts  This  is  a 
point  to  which  I  will  shortly  return. 

III.  The  definitely  acquired  facts  relative  to  regional  diag- 
nosis concerning  the  various  parts  which  enter  into  the  com- 
position of  the  central  ganglionic  masses  of  the  brain  can  be 
reduced  to  a  very  small  number  of  propositions. 

1st.  Regarding  lesions  confined  to  any  one  of  the  gray 
central  ganglia,  and  where  the  internal  capsule  is  not  in- 
volved, we  are  not  at  present  able,  from  clinical  examination, 
to  recognize  any  special  characters. 

(a.)  Thus  it  is  impossible  to  distinguish,  during  life,  a  lesion 
limited  to  the  lenticular  ganglion  from  one  confined  to  the 
caudated  ganglion,  and  lesions  of  the  thalamus  opticus  (though 
upon  this  last  point  there  is  reason  perhaps  for  some  reserve) 
generally  confound  themselves  clinically  with  those  produced 
in  the  two  compartments  of  the  corpus  striatum. 

The  symptoms  which  accompany  lesions.Jimited  to  the 
gray  central  ganglia  are  those  of  common  cerebral  hemiplegia. 
That  form  of  cerebral  hemiplegia  may  be  called  central,  to 
distinguish  it  from  motor  paralysis,  which  sometimes  results 
from  superficial  lesions,  and  which  in  distinction  I  will  call 
cortical  cerebral  hemiplegia. 

(#.)  Paralysis,  dependent  upon  lesions  of  the  gray  central 
ganglia,  is  generally  of  motion  only ;  disturbances  of  sensa- 
tion such  as  belong  to  cerebral  hemiancesthesia  are,  however, 
sometimes  added,  under  special  circumstances  to  which  we 
will  shortly  give  attention. 

(c.)  Hemiplegia,  dependent  upon  alterations  confined  to  the 
gray  ganglia,  is  generally  transitory,  passing,  lightly  marked 
not  indelible,  and  in  any  case  is  at  first  comparatively 
benign.  It  is  understood  that  in  formulating  this  proposi- 
tion I  remove  all  complications  capable  of  greatly  modify- 
ing the  picture  ;  such,  for  example,  would  be  the  eruption 
of  a  hemorrhage,  however  small,  into  a  ventricular  cavity. 


78  DISEASES   OF  THE  BRAIN. 

Grave  symptoms,  such  as  early  contractions,  or  epileptiforni 
convulsions,  almost  necessarily  ensue  in  such  cases,  and  more 
or  less  rapid  death  is  generally  the  necessary  consequence 
of  such  complication. 

The  relative  benignity  of  lesions  limited  to  the  gray  ganglia 
arises  in  part,  doubtless,  from  the  fact  that  these  ganglia  are 
scarcely  ever  affected  in  their  totality.  Thus  the  caudated 
ganglion,  for  example  (and  the  fact  is  explained  by  the 
method  in  which  the  vessels  going  to  it  are  distributed),  is 
never  destroyed  in  its  entire  extent,  at  least  by  itself,  that  is 
to  say,  without  the  participation  of  the  internal  capsule  or 
other  gray  ganglia.  On  the  other  hand,  the  transitory  char- 
acter of  a  paralysis  resulting  from  partial  lesion  of  the  cen- 
tral ganglionic  masses  may  indicate,  as  we  will  see,  a  sort  of 
functional  supplement  established  between  the  various  parts 
of  the  caudated  ganglion,  or  between  the  caudated  ganglion 
and  the  various  segments  of  the  lenticular  ganglion. 

2d.  Then,  again,  lesions  of  the  internal  capsule,  even  when 
strictly  limited  to  the  white  tract,  in  no  degree  including  the 
substance  of  the  gray  ganglia — these  lesions,  I  say,  generally 
produce  common  cerebral  hemiplegia  of  a  very  marked  and 
more  or  less  persisting  form.  Thus,  even  when  very  circum- 
scribed (principally  when  they  are  situated  low  down  at  the 
side  of  the  peduncle),  these  lesions  produce  a  motor  paralysis 
almost  necessarily  accompanied  by  late  contractions  ;  a  symp- 
tom of  bad  augury  in  these  troubles,  because  as  a  rule  it  an- 
nounces that  the  paralysis  will  resist  all  therapeutical  means. 

3d.  It  is  proper  to  establish  here  an  important  distinction. 
We  have  already  said  that  the  symptoms  differ  remarkably 
according  to  the  portion  of  the  internal  capsule  affected  by 
the  lesion. 

If  it  occupies  any  part  of  the  anterior  two-thirds  of  the 
capsule,  the  region  where  the  white  tract  separates  the  ante- 
rior extremity  of  the  lenticular  ganglion  from  the  head  of  the 
caudated  ganglion,  and  which  belong,  as  you  know,  to  the 
field  of  the  lenticulo-striated  artery,  the  paralysis  will  be  ex- 
clusively that  of  motion  ;  there  will  be  no  durable  trouble  of 
sensation. 


CENTRAL   ARTERIES. 


79 


On  the  contrary,  if  the  lesion  having  invaded  the  domain 
of  the  lenticulo-optic  arteries  should  extend  to  the  posterior 
third  of  the  capsule,  in  that  region  where  it  passes  between 
the  posterior  extremity  of  the  lenticular  ganglion  and  the 
thalamus  opticus,  the  presence  of  cerebral  hemiansesthesia 
would  be  almost  certain.  Most  frequently  the  lesion  extends 


Posterior  extremity, 
of  caudated  jiucleus\ 
B 


Corpus  CaHosum.and 
illarS  of  the  Arch. 

.ateral  Ventricle, 


Extl.WalL 


Horn  of  Amm 
andsphenbidal 
horn  of  lat.Yentricle: 


'portion  ihcWding 
internal  capsule). 


External  Capsule. 
'^Lenticular  Nucleus. 


FIG.  23.— Extra-lenticular  hemorrhagic  centre  on  a  plane  with  the  posterior  por 
tion  of  the  thalamus  opticus.     ( Cerebral  hemiancesthesia. ) 

to  several  parts,  and  paralysis  of  sensation  will  be  accom- 
panied with  a  more  or  less  marked  motor  hemiplegia.  But  it 
may  happen  that  cerebral  hemianaesthesia  will  occur  alone,  at 
least  as  a  permanent  phenomenon,  in  those  cases,  for  example, 
where  the  most  distant  parts,  the  most  posterior  portion  of 
the  internal  capsule  would  alone  be  definitely  altered  (Fig. 

23). 

In  the  preceding  expose  I  have  purposely  alluded  only 
to  truly  destructive  lesions  of  the  internal  capsule,  to  those 
which,  either  by  lacerations  or  necrosis,  produce  an  irrepa- 
rable loss  of  substance.  It  is  necessary,  however,  to  distin- 
guish those  cases  where  the  internal  capsule  is  not  directly 
involved,  but  affected  by  proximity  to  a  neighboring  phe- 
nomenon, that  is,  the  consequence  of  a  lesion  limited  to  the 


8o 


DISEASES   OF   THE   BRAIN. 


gray  ganglia  which  surround  the  capsules.  Thus  the  disten- 
tion  of  one  of  these  ganglia,  in  case  of  interstitial  hemor- 
rhage, might  compress  the  nerve- fibres  that  compose  the  in- 
ternal capsule  and  so  suspend  their  functions.  But  as  the 
nerve-fibres  in  such  cases  are  only  compromised  and  not  de- 
stroyed, the  paralytic  phenomena  resulting  from  that  com- 
pression (excepting  cases  of  tumor)  would  always  be  tempo- 
rary. 

The  combination  which  I  have  brought  to  your  notice  is 
frequently  met  in  the  clinic  of  intracerebral  hemorrhage  ;  it 
makes  a  somewhat  complicated  condition,  and  one  in  which 
the  interpretation  of  symptoms  might  be  rendered  difficult. 
In  this  way,  if  one  is  not  well  forewarned  of  the  difficulties, 

Primitive  lisemorragic  center 
in  internal  capsulej 

arcle  of  prixnit^cUer. 
Successive  extensions  from  ihe  center. 


Zxt.Wall 
Ext.  Capsule 


iteirial  Capsule. 

ICaudated  nucleus  of  corpus  strialum. 


FIG.  24. — Human  brain.  Section  through  the  anterior  portion  of  the  internal 
capsule,  showing  the  location,  mode  of  formation,  and  extension  of  hemorrhages  at 
the  anterior  portion  of  the  internal  capsule.  (Hemiplegias.) 

they  would  be  tempted  (and  the  error  has  often  been  com- 
mitted) to  attribute  certain  symptoms  to  destruction  of  some 
one  of  the  gray  ganglia,  as  to  the  thalamus  opticus,  or  the 


CENTRAL  ARTERIES.  8 1 

corpus  striatum,  which  were  only  the  result  of  a  neighboring 
accident  and  the  incidental  compression  of  the  internal  capsule. 

The  subject  is  worth  further  explanations. 

Let  us  suppose  the  recent  formation  of  a  hemorrhagic  cen- 
tre in  the  lieu  Selection.  The  blood  would  then  be  extrav- 
asated  outside  of  the  lenticular  ganglion,  virtually  into  the 
space  of  which  we  have  already  spoken  ;  and  the  third  seg- 
ment of  the  lenticular  ganglion,  otherwise  called  tine  putamen, 
would  generally  be  in  part  torn  away.  I  have  told  you  that 
under  such  circumstances  the  external  wall  of  the  extravasated 
spot,  including  the  convolutions  of  the  island  of  Reil,  the  ante- 
rior wall,  and  the  internal  capsule,  would  resist  the  pressure 
of  the  extravasated  blood,  while  the  gray  ganglia  are  gener- 
ally crowded  in  their  entirety  towards  the  ventricular  cavities. 
It  is  clear  that  the  substance  of  the  internal  capsule  would 
necessarily  be  more  or  less  forcibly  compressed  by  such  a 
change  (Fig.  24).  Respecting  the  symptoms  produced,  two 
conditions  might  ensue. 

Sometimes  the  extravasated  centre  is  restricted  to  those 
portions  of  the  lenticular  ganglion  which  correspond  to  the 
anterior  half  or  two- thirds  of  that  body  ;  that  is,  to  the  domain 
of  the  lenticulo-striated  artery.  In  consequence,  the  anterior 
part  of  tJie  internal  capsule  would  be  immediately  affected  by 
compression.  The  effect  would  be  exclusively  a  motor  hemi- 
plegia  of  the  opposite  side  of  the  body  (Fig.  22).  Sometimes, 
generally  extending  from  before  backward,  the  extravasation 
would  crowd  to  the  most  posterior  parts  of  the  lenticular 
ganglion  ;  pressure  would  then  be  made  upon  the  posterior 
part  of  the  internal  capsule,  and  symptoms  of  cerebral  hemi- 
anaesthesia  would  follow  those  of  motor  hemiplegia. 

Figures  24  and  25  will  enable  you  to  easily  recognize 
the  precise  locality,  and  the  mode  of  formation  and  exten- 
sion of  the  various  centres  of  central  hemorrhage  (see  also 
Fig.  23). 

One  word  more  upon  the  interpretation  of  these  facts. 
After  having  recognized  during  life  the  following  symptoms  ; 
motor  hemiplegia  with  hemianaesthesia,  and  at  post-mortem 
the  existence  of  a  spot  involving  the  lenticular  ganglion, 


82 


DISEASES   OF  THE  BRAIN. 


would  you  be  led  to  conclude  from  the  close  relation  of  these 
two  orders  of  facts  that  the  lenticular  ganglion  controlled  both 
sensation  and  voluntary  motion  of  the  opposite  side  ? 

Such  conclusion  would  not  be  very  legitimate,  for,  had  the 
patient  survived,  and  the  extravasation  absorbed  and  left  as 
a  representative  only  a  yellow  linear  cicatrix,  the  hemianaes- 
thesia,  and  even  the  motor  paralysis,  notwithstanding  partial 
destruction  of  the  lenticular  ganglion,  would  doubtless  have 
disappeared,  leaving  no  traces. 


Successive  extension 
of  primitive  center. 

I 


Tbgressrre  extension 
.of  primitive  center. 

9 


£ 


ernal  capsuikL 


FIG.  25.  —  Human  brain.  Section  through  the  posterior  portion  of  the  internal 
capsule,  showing  location,  mode  of  formation  and  extension  of  hemorrhages  at  the 
posterior  portion^of  the  internal  capsule.  (Hemiancesthesia.  ) 

That  which  has  been  said  respecting  hemorrhages  of  the 
lenticular  ganglion  applies  equally  to  hemorrhages  which  oc- 
cur in  the  posterior  portion  of  the  bodies  of  the  thalami  op- 
tici.  These  hemorrhages  result  from  a  rupture  of  the  external 
anterior  optic,  or  lenticulo-optic  artery.  They  are  generally 
indicated  by  a  more  or  less  marked  hemiplegia,  and  nearly 
always  also  by  a  more  or  less  complete  hemianaesthesia,  pro- 
vided the  hemorrhage  be  sufficiently  extensive.  Should  it 


CENTRAL  ARTERIES.  83 

be  at  once  concluded  (as  so  many  authors  have  said  and  still 
repeat)  that  the  thalami  optici  are  the  seat  of  common  sensa- 
tion ?  Incontestably,  no  ;  besides,  it  would  be  easy  to  cite 
numbers  of  facts  where  a  hemorrhagic  lesion  of  the  posterior 
tract  of  the  thalamus  opticus  produced,  in  the  first  phase  of 
the  malady  (that  is  to  say,  when  conditions  of  pressure  existed), 
sensitive  and  sensorial  disturbances,  which  disturbances  ceased 
in  the  later  stage,  that  is,  from  the  date  where  reabsorption 
removed  the  pressure  from  the  posterior  or  lenticulo-optic 
region  of  the  internal  capsule. 

It  would  be  superfluous  to  continue.  I  think  I  have  suf- 
ficiently demonstrated  that  in  regional  diagnosis,  as  concerns 
the  various  parts  of  the  central  masses  of  the  brain,  it  is  the 
participation  or  the  non-participation  of  the  anterior  or  pos- 
terior regions  of  the  internal  capsule  which  determines  the 
situation. 

IV.  The  propositions  which  I  have  offered  possess  a  prac- 
tical interest  which  will  not  escape  your  attention.  Hitherto 
they  have  been  presented  in  the  form  of  a  postulate.  It  is 
now  proper  to  establish  them  by  demonstration  ;  or,  in  other 
terms,  to  give  you  that  proof  which  will  serve  to  insure  them 
a  permanent  place  in  the  records  of  human  pathology. 

We  ought  also  to  give,  as  far  as  we  can,  the  theory  of  the 
facts  concerned  ;  that  is,  we  should  enter  as  far  as  possible 
into  the  anatomical  and  pathological  reasons.  To  accom- 
plish this,  we  are  obliged  to  return  once  more  to  the  normal 
anatomy  of  the  brain,  in  order  to  complete  in  some  respects 
the  ideas  already  acquired. 

In  the  preceding  exposd,  the  predominant  role  in  the  patho- 
logical anatomy  of  the  central  masses  which  is  sustained  by 
the  two  main  departments  of  the  internal  capsule,  has  been 
shown,  together  with  the  proof,  and  they  justify  the  descrip- 
tions which  we  have  made  concerning  the  anatomical  consti- 
tution of  the  grand  tract.  Now,  it  is  necessary  to  go  a  little 
further,  and  seek  for  that  which  is  peculiar  to  the  anterior  or 
lenticulo-striated  region  of  the  capsule,  in  distinction  from 
that  which  is  peculiar  to  the  posterior,  or  lenticulo-optic  re- 


DISEASES   OF  THE   BRAIN. 


gion,  where  lesions  produce  only  symptoms  of  cerebral  hemi- 
ancestJiesia.     We  will  commence  with  the  last. 

A.  The  recent  anatom- 

Peduncular  fibres,  going! 
to  Corpus  striatum  ; 


Lenticular  nucleus. 


ical  researches  of  Mey- 
nert  have  furnished  us  in 
this  respect  with  very 
important  information. 
They  have  been  given  in 
detail  in  a  work  of  one  of 
his  auditors,  Huguenin, 
Professor  at  Zurich.1 
They  consist  of  dissec- 
tions and  also  in  compari- 
sons of  thin  slices,  hard- 
ened, and  examined  by 
transmitted  light. 

The  brain  being  placed 
upon  its  base,  the  lateral 
ventricles  are  opened  in 
such  manner  as  to  lay 
bare  the  superior  face  of 
the  central  masses — those 
which  are  contiguous  to 
the  various  parts  of  the 
isthmus ;  after  that,  by 
minute  dissection,  are 
PC~  successively  removed  : 
1st,  tegmentum,  or  upper 

part  of  the  peduncle  ;  2d,  the  tubercula  quadrigemina  ;   3d, 
the  entire  thalami  optici. 

This  being  done,  the  inferior  parts  of  the  peduncle  (pes9 
crusta)  are  brought  to  view,  and  higher  up  (in  the  region 
of  the  internal  capsule),  the  fasciculi  of  peduncular  fibres  run- 
ning to  the  caudated  ganglion.  The  fibres  belonging  to  the 
internal  capsule,  which  goto  the  lenticular  ganglion,  occupy  a 
plane  situated  beneath  and  external  to  the  preceding  fasciculi. 


Tasiculus^ol  direct  peduncular  fibres 
going  to  cortical  substance  of  occip'l  loBe. 


1  Allgem.  Path,  der  Krankh.,  etc.,  p.  119,  Fig.  82,  Zurich,  1873. 


CENTRAL   ARTERIES.  85 

Attentively  observing  the  internal  and  posterior  parts  of 
the  diverging  fibres  thus  exposed,  there  is  to  be  discovered  a 
fasciculus,  detached  as  it  were  from  the  main  body,  and  which, 
without  entering  the  substance  of  the  gray  ganglia,  turns 
backward  as  soon  as  it  reaches  the  inferior  border  of  the  len- 
ticular ganglion  (Fig.  26). 

That,  you  see,  is  a  direct  fasciculus,  since  the  fibres  of  which 
it  is  composed  enter  the  diverging  fibres  without  stopping  in 
the  gray  substance  of  the  central  masses  ;  it  is,  moreover,  as 
the  description  shows,  a  separate  fasciculus. 

What  is  the  destination  of  these  nerve-fibres  ?  With  man 
it  is  nearly  impossible  to  say ;  but  in  some  monkeys,  accord- 
ing to  Meynert,  their  course  can  be  easily  followed  into  the 
body  of  the  white  substance  of  the  occipital  lobe,  just  outside 
the  posterior  cornu  of  the  lateral  ventricle  (cor nu  posterius, 
ventriculi  later  alls}.  They  finally  terminate  in  the  body  of 
the  gray  cortical  substance  of  the  occipital  lobe. 

B.  Does  there  exist  any  anatomical  reason  for  supposing 
that  the  fasciculus  in  question  is  really  composed  of  centripetal 
fibres,  having  as  a  function  the  transmission  of  sensitive  im- 
pressions to  the  surface  of  the  posterior  regions  of  the  brain  ? 
Meynert  so  thinks,  and  for  the  reason  that  (according  to  him) 
these  fibres,  by  comparing  thin  slices,  can  be  followed  down 
the  length  of  the  cerebral  peduncle  to  the  protuberance 
(foot,  inferior  part)  ;  in  the  peduncle  they  occupy  the  most 
external  part.  Reaching  the  protuberance,  they  go  to  the 
posterior  part  of  the  pyramidal  fasciculus,  and  maintain  very 
nearly  the  same  location  in  the  anterior  pyramid  to  the  point 
of  decussation.  There  (contrary  to  that  which  occurs  with 
the  most  internal  fasciculi  of  the  pyramid,  which  pass  into 
the  lateral  columns  of  the  spinal  cord)  they  decussate,  and 
then  join  the  posterior  spinal  fasciculi.  I  am  not  able  to  guar- 
antee the  entire  authenticity  of  the  last  part  of  the  tract  as- 
signed by  Meynert  to  the  fibres  which  compose  the  most  pos- 
terior portion  of  the  internal  capsule. 

Such  is  at  present  the  share  of  normal  anatomy,  and  it 
affords  an  independent  illumination  of  our  subject.  But  how- 
ever important  this  aid,  it  would,  without  pathological  anat- 


86  DISEASES   OF  THE   BRAIN. 

omy  and  experimentation,  be  entirely  insufficient  to  solve 
the  problem  ;  and  once  more  we  repeat  that  physiology  and 
pathology  cannot  be  deduced  from  an  unassisted  contempla- 
tion of  pure  anatomical  facts. 

C.  We  are  now  at  the  proper  point  to  introduce  clinical  and 
anatomico-pathological  proofs.  At  the  present  time  they  are 
abundant.  It  will  suffice  to  note  the  observations  of  Ludwig 
Tiirck,  the  pioneer  in  this  road,1  those  of  his  compatriot 
Rosenthal,2  those  which  I  have  collected  at  the  Salpetriere, 
and  finally  those  which  have  been  gathered  by  Veyssiere 
and  Rendu,  the  first  in  his  inaugural  thesis,3  the  second 
in  his  thesis  for  agregation* 

The  comparison  of  these  observations  gives  the  following 
uniform  results:  1st,  that  lesions  confined  to  the  posterior 
lenticulo-optic  region  of  the  internal  capsule  necessarily  result 
in  that  form  of  hemianaesthesia  which  I  call  cerebral,  and  in 
which  sensations  controlled  by  the  cerebral  nerves,  that  is, 
the  optic  and  olfactory  nerves,  are  so  affected  as  to  faithfully 
reproduce  the  characteristics  of  hysterical  hemianaesthesia ; 
2d,  that  on  the  contrary,  in  all  cases  where  the  lesions  involve 
only  that  part  of  the  capsule  which  lies  between  the  lenticular 
ganglion  and  the  head  of  the  caudated  ganglion,  anaesthesia 
is  absent. 

These  contributions  of  pathological  anatomy  and  clinic  are 
by  themselves  of  incontestable  and  prime  importance  ;  but 
combined  with  the  testimony  of  pure  anatomy,  they  assume 
a  standard  value. 

That  is  not  all ;  experimentation  has  in  turn  brought  its 
share  of  facts,  which  also  repeat  the  same  story. 

Under  the  guidance  of  pathological  knowledge,  experi- 
mentation has  corrected  itself.  It  had  previously  been  sup- 


1  Tiirck,  see  Charcot. — Lectures  upon  Maladies  of  the  Nervous  System,  t.  I.,  2d 
ed.,  p.  315. 

2  Rosenthal,  Klinik  der  Nervenkrankheiten,  2d  Aufl.,  Stuttgart,  1875. 

3  R.  Veyssiere,  Recherches  cliniques  et  experimentales  sur  1'hemianesthesie  de 
cause  cerebrale.     These  de  Paris,  1874. 

*  H.  Rendu,  Des  anesthesies  spontanees.    These  d'agregation,  Paris,  1875,  pp. 
27  and  95. 


CENTRAL  ARTERIES. 


Lenticular  nucleus  1 
Section  of  ant.  portion"*    ! 
.of  internal  capsule;    | 
Caudatedn{id,ei 
A  of  corporal: 


Inkcapsuk 


posed  that  the  centre  of  sensitive  impressions  was  not  in  the 
brain  proper,  nor  in  the  thalami  optici,  but  lower  down,  in 
the  protuberance,  or  perhaps  in  the  crura  cerebri. 

Pathology  controverted 
that  assertion,  in  showing 
that  a  lesion  situated  above 
those  points,  in  certain  re- 
gions of  the  brain  itself,  was 
quite  sufficient  to  invariably 
produce  a  total  hemianaes- 
thesia.  Recent  experimental 
researches  made  by  Duret 
and  Veyssiere,  in  the  labor- 
atory of  Vulpian,  have  given 
results  also  in  conformity 
with  pathological  teaching. 

An  ingenious  instrument, 
consisting  of  a  trocar  from 
which  at  a  desired  moment 
escapes  a  spring,  is 
duced  through  the  cranial 
wall  into  the  central  masses,  to  a  depth  and  in  a  direction 
calculated  through  previous  experiments.  Thus,  with  a  little 
experience,  either  of  the  two  portions  of  the  internal  capsule 
can  by  itself  be  injured. 

If  in  these  experiments  the  lesion  reaches  the  posterior 
capsule,  hemiansesthesia  of  the  opposite  side  of  the  body 
certainly  ensues  ;  generally  there  is  associated  with  it  a  cer- 
tain degree  of  motor  paralysis ;  this  (motor  paralysis),  on  the 
contrary,  occurs  unaccompanied  with  anaesthesia  whenever 
the  lesion  is  confined  to  any  point  of  the  anterior  two-thirds, 
leaving  the  posterior  third  of  the  internal  capsule  untouched. 
(Figs.  27  and  28.) 

Such  in  brief  are  the  substantial  results  of  these  experiments. 

After  the  foregoing,  you  will  see  that  everything  concurs  to 
establish  the  existence  of  direct  fasciculi  of  centripetal  nerve- 
fibres  in  the  posterior  part  of  the  internal  capsule,  having  for 
function  the  conduction  of  sensitive  impressions  coming  from 
the  opposite  side  of  the  body  towards  the  centre. 


ilnt.  cap&ula 
of  optic  nerves, 

FIG.   27.  —  Transverse  section  of  a  dog's 
intro-    brain,  five  millimetres   anterior  to  the  optic 
chiasma. 


88  DISEASES   OF  THE  BRAIN. 

Emanating  from  the  foot  of  the  central  peduncle,  these 
fasciculi,  as  they  leave  the  capsule,  run  directly  towards  the 
formation  of  the  diverging  fibres,  without  communicating 
with  the  gray  ganglia  of  the  central  masses.  Near  their  ori- 
gin, that  is,  at  the  inferior  part  of  the  capsule,  these  fasciculi, 
pressed  into  a  narrow  space,  might  be  affected  in  great  num- 

Caudat^d  nuclei 

•  %     Inf.  capsule,  post.portion. 


FIG.  28. — Transverse  section  of  a  dog's  brain,  on  a  plane  with  the  tubercula  mam- 
millaria.  — ( Carville  and  Duret. ) 

bers  by  a  single  stroke,  by  a  very  minute  lesion,  and  be  fol- 
lowed by  very  marked  anaesthesia.  It  can  be  understood,  on 
the  other  hand,  that  higher  up,  on  a  level  with  the  foot  of 
the  diverging  fibres,  a  lesion  of  the  same  extent  would,  by 
reason  of  the  divergence  of  the  fibres,  produce  much  less 
marked  effects.  This  is,  in  fact,  the  case.  There  exist  many 
examples  of  well-marked  hemianaesthesia  in  connection  with 
slight  lesions  of  the  foot  of  the  diverging  fibres. 

It  should  now  be  determined  if  lesions  extended  to  the 
occipital  lobes,  and  especially  to  their  gray  cortex,  produce 
crossed  hemianaesthesia.  Unhappily  the  facts  which  can  be 
cited  in  that  regard  are  not  sufficiently  explicit,  and  the  ques- 
tion must  remain  in  suspense  until  more  ample  information 
is  obtained.1  However  that  may  be,  it  is  now  recognized 

1  In  the  observations  which  I  have  collected  of  superficial  softenings  of  the 
occipital  lobe,  there  were  frequent  hyperaesthesias,  painful  sensations  of  all  sorts 
in  the  opposite  limbs,  hallucinations  of  vision,  etc.,  as  well  as  hemianaesthesia  or 
amblyopia. 


CENTRAL  ARTERIES.  89 

that  the  fasciculi  which  compose  the  posterior  part  of  the  in- 
ternal capsule,  and  their  direct  emanations,  cannot  be  con- 
sidered as  a  centre  of  sensitive  and  sensorial  impressions. 
These  fasciculi  can  only  represent  a  highway,  a  cross-road, 
where  the  centripetal  fibres  of  which  it  is  composed  are  all 
represented  before  diverging  to  the  superficial  parts  of  the 
brain. 


TENTH   LECTURE. 


CEREBRAL  HEMIAN^STHESIA  (CONTINUED).— CROSSED   AM- 
BLYOPIA.— LATERAL   HEMIOPIA. 


Summary  t— Resume  of  the  Characters  of  Cerebral  Hemianeesthesia.— 
Its  Resemblance  to  Hysterical  Hemian&esthesia. — Anaesthesia  In- 
volves General  Sensibility  in  its  Various  Forms,  and  also  the  Special 
Senses.— Hysterical  Amblyopia. — Ophthalmoscopic  Examination. — 
Concerning  Functions.— Diminution  of  Visual  Acuteness.— Concen- 
tric and  General  Contraction  of  the  Field  of  Vision,  etc. — Crossed 
Amblyopia  with  Hemianaesthesia  from  Cerebral  Causes. — Symptoms. 
— Lesions  of  the  Cerebral  Hemispheres  which  Produce  Hemianaesthe- 
sia  Produce  also  Crossed  Amblyopia  and; not  Lateral  Hemiopia.— 
Hemiopia. — Hypothesis  of  Semidecussation. — Unilateral  Homologous 
Hemiopia.— Varieties  of  Hemiopia. 

GENTLEMEN  : 

In  the  last  lecture  I  attempted  to  prove  that  a  peculiar  form 
of  hemianaesthesia  is  a  necessary  consequence  of  lesions  in 
the  posterior  regions  of  the  internal  capsule,  or  of  its  emana- 
tions in  the  diverging  fibres,  no  matter  whether  these  lesions 
be  destructive,  compressive,  or  suspensive,  the  value  of  which 
last  term  I  will  soon  explain. 

I  have  based  this  proposition  not  alone  upon  pathological 
and  clinical  anatomy,  but  also  upon  the  facts  of  experimenta- 
tion. I  have  given,  too,  some  contributions  from  pure  anatomy 
which,  to  be  sure,  in  certain  respects,  require  confirmation, 
but  such  as  they  now  are,  they  permit  us  to  look  into  the 
mechanism  by  which  the  hemianaesthesia  in  question  is  pro- 
duced. 

There  are  some  features  relative  to  the  totality  of  symptoms 
and  their  anatomical  and  physiological  interpretation,  that  I 
have  purposely  left  in  shadow,  so  as  not  to  overcrowd  the 
picture.  I  propose  now  to  recur  to  them. 


CROSSED   AMBLYOPIA. — LATERAL   HEMIOPIA.  9 1 

I.  First,  let  me  in  a  few  words  recite  the  clinical  characters 
of  that  kind  of  hemianaesthesia  which  I  propose  to  call  cere- 
bral hemiancesthesia,  in  order  to  distinguish  it  from  all  other 
forms  of  obscuration  or  diminution  of  sensibility,  the  origin 
of  which  is  not  recognized  as  depending  upon  a  lesion  of  the 
brain  proper. 

It  is  only  lately  that  cerebral  hemianaesthesia  from  gross 
organic  lesion — "  coarse  disease"  as  H.  Jackson,  with  a  lib- 
erty quite  English,  terms  it — has  been  the  object  of  attentive 
study.  The  picture  it  presents  is  exactly  that  of  hysterical 
hemianaesthesia  ;  this  last,  being  at  present  better  known, 
will  more  naturally  serve  as  a  prototype. 

Hysteria,  you  know,  presents  a  unilateral  anaesthesia. 
Total  anaesthesia  is  relatively  rare.  An  antero-posterior  plane 
through  the  median  line  of  the  body  marks  the  limit  of  insen- 
sibility, which  line  upon  the  trunk,  however,  is  somewhat 
overstepped  on  the  sternum  in  front,  and  on  the  spinal  crest 
behind.  This  is  a  detail  of  secondary  importance. 

The  head,  the  limbs,  and  the  body  on  one  side,  then,  are 
all  affected  at  the  same  time.  There  may  naturally  be  de- 
grees in  the  functional  disturbance,  but  more  frequently  it 
embraces  all  kinds  of  common  sensibility  ;  the  sense  of  touch, 
of  pain,  and  of  temperature  are  often  simultaneously  obscured 
or  suppressed. 

The  insensibility  extends  to  the  profound  parts  ;  it  affects 
the  muscles,  which  may  be  electrically  excited  without  the 
patient's  consciousness  of  it.  The  mucous  membranes  are  not 
spared.  Finally,  let  us  add  —  and  this  is  the  point  which 
above  all  others  I  just  now  desire  to  make  prominent — hemi- 
anaesthesia does  not  include  common  sensation  alone,  it  in- 
volves also  the  sensorial  apparatus  of  the  same  side  of  the 
body  affected  with  cutaneous  anaesthesia,  and  that  sensorial 
hemiancesthesia  takes  in,  not  only  the  nerves  coming  from 
the  bulb,  such  as  those  of  taste  and  hearing,  but  also  the 
nerves  of  smell  and  vision,  the  origins  of  which  are  in  the 
brain  proper. 

Such  is  the  common  picture  of  the  hemianaesthesia  of  hys- 
teria. If  we  compare  the  hemianaesthesia  really  cerebral 


92  DISEASES   OF  THE   BRAIN. 

with  this,  we  will  see  a  perfect  resemblance,  even  to  the 
smallest  detail. 

We  have  already  carefully  brought  to  light  the  resemblance 
as  concerns  common  sensation,1  and  Magnan  has  done  the 
same  in  that  which  concerns  troubles  of  hearing,  smell,  and 
taste.2  I  see  nothing  to  add  to  what  has  been  said  upon  the 
subject.  Lately  we  have  been  more  particularly  occupied 
with  those  phenomena  which  concern  vision.  In  my  service 
at  Salpetriere,  Dr.  Landolt  has  devoted  himself  to  researches 
in  that  direction,  the  results  of  which  merit  brief  mention. 

It  seems  to  me  of  interest  to  offer  some  facts  showing  that, 
even  as  relates  to  visual  troubles  (and  this  you  will  soon  rec- 
ognize as  of  great  consequence),  absolutely  the  same  things 
occur  in  real  cerebral  lesions  as  with  those  simply  hysterical. 
Abstraction  seems  to  exhibit  here  its  proverbial  changeabil- 
ity ;  the  unilateral  amblyopia  of  hysterics  differs  in  no  essen- 
tial character  from  the  crossed  cerebral  amblyopia  recognized 
as  having  an  organic  origin. 

Let  us  first  examine  hysterical  amblyopia. 

II.  1st.  Here  diminution  more  or  less  pronounced,  and 
sometimes  (though  rarely)  absolute  loss  of  vision  upon  the 
side  corresponding  to  the  hemianaesthesia,  is  the  first  easily 
recognized  symptom. 

2d.  A  more  minute  study  develops  the  following  peculiar- 
ities :  There  exist  in  the  bottom  of  the  eye  no  alterations 
appreciable  by  the  opthalmoscope.  The  pupil  and  retina  are 
entirely  normal.  Comparative  examination  of  the  posterior 
portions  of  the  two  eyes  shows  also  no  appreciable  difference 
in  their  vascularization. 

If  the  ophthalmoscope  does  not  betray  alterations  in  am- 
blyopia of  hysteria,  it  is  not  the  same  with  subjective  func- 
tional phenomena.  This  is  what  is  learned  through  that 
method  of  examination. 


1  Charcot. — Lectures  upon  Maladies  of  the  Nervous  System,  ist  ed.,  1872. 
3  Magnan. — Upon  Hemianaesthesia  of  General  Sensibility  and  of   the  Special 
Senses  in  Chronic  Alcoholism.     Gaz.  hebd.,  1873,  pp.  729  and  746. 


CROSSED   AMBLYOPIA. — LATERAL   HEMIOPIA.  93 

3d.  Visual  acuteness,  studied  after  ordinary  rules,  often 
shows  itself  reduced  by  one-half  or  even  more. 

4th.  There  exists  a  general  and  concentric  contraction  of  the 
field  of  vision. 

5th.  Careful  analysis  has  recognized  certain  peculiarities 
which  deserve  attention  ;  they  concern  the  concentric  and 
general  contraction  of  the  field  of  vision  for  colors. 

Many  authors,  among  others  Galezowski,  have  heretofore 
remarked  the  frequent  accompaniment  of  achromatopsia  and 
dyschromatopsia  with  hysteria.  These  are  the  special  points 
of  observation  made  in  my  service  by  Landolt. 

I  would  recall  to  you  that  in  the  normal  state,  all  regions  of 
the  visual  field  are  not,  for  some  reason,  equally  apt  in  percep- 
tion of  colors.  There  are  colors  for  which  the  visual  field  is 
physiologically  more  extended  than  for  others,  and  these 
differences  in  the  extent  of  the  visual  field  always  occur  in 
the  same  subject  according  to  the  same  law  for  each  color. 
Thus  the  widest  field  of  vision  is  for  blue  ;  then  yellow,  then 
orange,  red,  green,  and  lastly  violet,  which  is  only  perceived 
by  the  most  central  parts  of  the  retina.  Now,  in  the  patho- 
logical condition  with  which  we  are  occupied,  the  normal 
condition  exists,  though  in  various  degrees  exaggerated. 
Indeed  the  various  circles  which  in  this  investigation  corre- 
spond to  the  limits  of  vision  for  each  color,  are  contracted 
concentrically  in  a  more  or  less  marked  manner,  but  still 
based  upon  the  law  recognized  for  the  normal  state. 

From  this  you  can  easily  foresee  the  numerous  combinations 
which  may  arise  in  cases  of  hysteria  where  this  kind  of  am- 
blyopia  has  attained  a  high  degree.  The  violet  circle  may 
contract  to  nothing,  then  as  the  malady  advances  the  same 
will  occur  consecutively  with  the  green,  red,  and  orange  ; 
the  yellow  and  blue  remain  to  the  last ;  observation  demon- 
strates that  these  are  the  two  colors  for  which  sensitiveness 
is  longest  preserved  in  cases  of  hysteria.  Finally,  in  extreme 
cases,  it  may  happen  that  perception  of  all  colors  ceases,  and 
then  to  the  eyes  of  the  patient  colored  objects  would  all  be- 
come reduced  to  the  appearance  of  a  sepia  drawing. 

Such  is  the  series  of  phenomena  which  we  have  over  and 


94  DISEASES  OF  THE  BRAIN. 

over  observed  in  hysterical  amblyopia.  Now,  these  are  all 
met  with  in  their  different  shades,  in  various  cases  of  crossed 
amblyopia  accompanied  with  hemianaesthesia  and  arising 
from  a  lesion  in  the  centre  of  the  brain,  such  as  we  have  re- 
cently examined.  The  same  is  true  of  diminution  of  visual 
acuteness  ;  of  concentric  and  general  contraction  of  the  visual 
field  of  colors,  even  where  no  pathognomonic  lesions  at  the 
bottom  of  the  eye  are  appreciable  with  the  ophthalmoscope, 
etc.1 

I  insist  especially  upon  this  last  characteristic,  because  it 
permits  a  clear  separation  of  the  functional  trouble  from  those 
usually  caused  by  intercranial,  organic  lesions.  I  allude  to 
the  alterations  at  the  bottom  of  the  eye,  easily  discovered 
with  the  ophthalmoscope,  and  commonly  known  under  the 
name  of  papillary  strangling  or  neuro-retinitis,  and  which  is 
so  frequently  seen  as  a  consequence  of  encephalic  tumors, 
whatever  may  be  their  nature  or  location?  and  also  following 
various  lesions  acting  more  or  less  directly  on  the  optic 
bands. 

In  making  known  to  you  that  crossed  amblyopia  is  a  con- 
sequence of  lesions  within  the  brain,  I  have  stated  a  fact  of 
major  importance  for  the  theory  of  cerebral  localization.  But 
it  cannot  escape  you  that  this  fact  is  in  formal  contradiction 
to  generally  diffused  ideas.  Indeed,  if  the  theory  put  forth  in 
1860,  by  Alb.  de  Graefe,3  and  which  still  appears  to  hold  un- 
divided sway,  as  witness  an  interesting  work  recently  pub- 


1  New  researches  made  for  me  by  Landolt  have  demonstrated  that  contraction 
of  the  field  of  vision  for  colors,  in  ovarian  hysteria  with  hemiansesthesia,  is  always 
experienced  in  both  eyes  at  the  same  time ;   only  it  is  incomparably  more  pro- 
nounced in  the  eye  corresponding  to  the  side  affected  with  the  anaesthesia.     The 
same  peculiarity  is  encountered  in  all  cases,  which  have  been  examined  in  this  re- 
spect, of  cerebral   hemiatuzsthesia  arising  from  organic  lesions.     Therefore    the 
term  crossed  amblyopia,   used  in  these  lectures,  will  not  be  taken  as  absolutely 
literal,  since  the  obscuration  of  sight  affects,  unequally  to  be  sure,  both  eyes. 

2  See  upon  this  subject  the  interesting  work  of  Dr.  Annuske. — Die  Neuritis 
Optica  bei   Tumor   Cerebri,  in  Arch,  fur  Ophthalmologie,  19  Bd.,  Abth.  III., 
I873.  P-  165. 

3  A.  de  Graefe. — Gazette  hebdomadaire,  1860,  p.  708.     See,  also,  Vortrage  aus 
der  V.  Graefe' schen  Klinik.     Monatsbl.  f.  Augenhlkde.,  1865,  Mai. 


CROSSED   AMBLYOPIA. — LATERAL   HEMIOPIA.  95 

lished  by  Dr.  Schoen,1  be  credited,  it  is  not  crossed  amblyo- 
pia  which  determines  exclusively  unilateral  lesions  of  the 
brain,  but  a  different  visual  trouble,  namely,  lateral  homol- 
ogous hemiopia  ;  in  other  words,  a  cerebral  lesion  of  the  left 
substance  of  the  brain  should,  according  to  the  theory  in 
question,  produce  suppression  or  obscuration  of  the  right 
half  of  the  visual  field,  and  the  reverse  in  case  of  a  lesion  in 
the  right  half  of  the  brain. 

I  believe  that  I  can  protest  against  this  theory  as  being  at 
least  too  absolute,  and  I  offer  against  it  the  following  propo- 
sition :  cerebral  lesions  of  the  hemispheres  zvhtch  produce  hemi- 
an&sthesia  produce  also  crossed  amblyopia,  and  not  lateral 
hemiopia. 

I  am  not  prepared,  let  it  be  well  understood,  to  decide  that 
lateral  hemiopia  is  never  the  consequence  of  a  lesion  in  the 
substance  of  the  brain,  but  I  am  disposed  to  believe  that 
such  cases,  if  they  really  exist,  are  phenomena  of  contiguity — 
the  effects,  for  example,  of  a  more  or  less  direct  participation 
of  the  optic  bands.  I  do  not  believe  that  there  now  exists  a 
single  observation  clearly  showing,  except  in  this  way,  the 
development  of  lateral  hemiopia  as  a  consequence  of  a  lesion 
of  the  posterior  part  of  the  internal  capsule  or  the  foot  of 
the  diverging  fibres,  while  a  number  of  facts  exist  where  such 
a  lesion  has  produced  crossed  amblyopia  with  all  the  charac- 
teristics that  we  have  just  assigned  to  it. 

III.  We  must  give  some  details  relative  to  the  symptoms 
of  hemiopia  and  the  presumed  anatomical  cause  of  its  develop- 
ment. 

You  know  that  this  singular  phenomenon,  so  often  observed 
in  clinic,  has  long  since  suggested  an  anatomical  hypothesis 
according  to  which  the  optic  nerves  in  man  do  not  make  a 
complete  decussation  in  the  optic  chiasma,  but  that  which  is 
called  a  semidecussation.  That  hypothesis  is  an  old  one.  It  is 
generally  attributed  to  Wollaston,  but  it  is  really  due  to  New- 
ton y  who  expressed  it  in  1704,  in  his  Treatise  upon  Optics^  and 

1  Schoen. — Archiv  der  Heilkunde,  1875,  ist  Heft. 


96  DISEASES   OF  THE  BRAIN. 

which  Vater,  in  1723,  employed  to  explain  three  cases  of  hemi- 
opia  which  had  fallen  under  his  observation.1  I  will  recall  the 
hypothesis. 

Among  the  nerve-tubes  which  form  the  bands  of  the  optic 
nerves  there  are  those  which,  as  has  been  said,  decussate 
in  the  chiasma  and  those  which  do  not.  (See  Fig.  29.) 
These  last,  that  is,  the  non-decussating  nerve-tubes,  occupy 
the  external  sides  in  the  bands,  in  the  chiasma,  and  also  in  the 
optic  nerves  and  the  retina,  whereas  at  all  of  these  points  the 
fasciculi  which  decussate  occupy  the  internal  sides.  It  follows 
that  the  non-decussating  fasciculi,  of  the  left  band,  for  example, 
being  affected,  would  affect  the  left  half  of  the  retina  of  the 
left  eye,  while  the  decussating  fasciculi  of  the  same  band  would 
affect  the  left  half  of  the  right  eye,  the  fasciculi  of  the  right 
optic  bands  operating  of  course  after  the  same  principle  in- 
versely. 

In  other  words,  the  fasciculi  which  compose  the  optic  band 
of  the  left  side  would  go  to  the  left  half  of  each  retina,  and 
the  reverse  would  occur  with  the  nerve-fasciculi  coming  from 
the  optic  bands  of  the  right  side. 

It  must  be  remembered  that  anatomically  speaking  this 
arrangement  of  the  optic  nerve-fibres  is  entirely  hypothetical. 
If,  indeed,  various  authors,  among  others  Hannover,2  Longet, 
Cruveilhier,  Henle,3  and  more  recently  Gudden,4  have  thought 
themselves  able  to  offer  anatomical  proof,  there  are  others, 
such  as  Biesiadecki,8  E.  Mandelstamm,6  and  Michel,7  who  con- 
tradict it,  and  appealing  to  the  same  order  of  arguments 

1  Knapp. — Archives  of  Scientific  Medicine,  New  York,  1872. 

2  Hannover. — "  Das  Auge,"  Beitrage  zur  Anatomic,  Physiologic,  und  Patholo- 
gic dieses  Organs,  Leipzig,  1872. 

3  Henle. — Nervenlehre.     Ueber  die  Kreutzung  im  Chiasma  Nervorum   Optico- 
rum. 

4  Gudden. — Arch,  fur  Ophthalmologie,  1874,  t.  20,  2d  Abth. 

5  E.  Biesiadecki. — Ueber  das  Chiasma  Nervorum  Opticorum  des  Menschen  und 
der  Thiere.     Wiener  Sitzber.  d.  math.  Naturwiss.  Classe  B.,  d.  42  Jahrg.  1861, 
p.  86. 

6  E.  Mandelstamm. — "  Ueber  Sehnervenkreuzung  und  Hemiopie."     Arch,  fur 
Ophthalmologie,  t.    16,  1873,  p.  39. 

1  Michel. — Ueber  den  Bau  des  Chiasma  Nervorum  Opticorum.  Same  work,  p. 
59,  Taf.  I.,  Fig.  IV.  See  also  Bastian,  The  Lancet,  1874,  July  25,  p.  112. 


CROSSED   AMBLYOPIA. — LATERAL   HEMIOPIA. 


97 


attempt  to  demonstrate  that  the  nerve-fibres  of  the  optic 
nerves,  even  in  man,  submit  to  a  complete  decussation.  In 
short,  it  may  be  said  that  at  present  the  question  is  far  from 
being  settled.  I  repeat  that  the  semidecussation  is  only 
an  hypothesis  ;  but  that  hypothesis  explains,  far  better  than 
any  of  its  substitutes,  all  the  facts  observed  in  clinic.  In  the 
scheme  herewith  given  it  will  be  seen  how  easily  it  serves  to 
interpret  the  various  modes  of  hemiopia.  (Fig.  29.) 


Sfemi- decussation  in  chiastna., 
Xfisionfiere  would  produce  temporal.hemiopia.i 

litres  decussating  in -chiasma 


^on-decussating  fibres  in-chiasma, 


I  esloTL  here  .pro  duces  nasal  heml 


L  esion  of  optic  £ancL 
producing  right  lateral 
hemiopia 


right  eys 
•/"//  running' to  leflliemispli^ref 

.esionJiece.pMaiacea  nasal  "hemlopia 


I  eft  Hemi  sphere .  Lesion 
here  would  produce  crossed?, 
light  atnbtyupia .  \\ 

Tibree  from  rigKl  \\ 
eye .  ending  in  left  ^hemisphere 


lemisphere. 
'J)ecussation  Lack  of  genicular  todies* 


FIG.  29. — Scheme  to  explain  the  phenomena  of  lateral  hemiopia  and  crossed  am- 
blyopia. 

We  will  first  consider  unilateral  homologous  hemiopia,  that 
which,  according  to  writers,  can  occur  only  as  the  direct  con- 
sequence of  an  intracerebral  lesion  of  the  brain.  It  is  clear 
that  according  to  the  theory,  a  lesion  situated  at  5  in  such 
way  as  to  interrupt  the  tract  of  the  fasciculi  of  the  left  optic 
band,  those  fibres  which  crossed  in  the  chiasma  (d),  and  also 
7 


98  DISEASES   OF  THE  BRAIN. 

those  which  did  not  cross  (a),  would  result  in  affecting  the  left 
half  of  each  retina  (//),  in  other  words,  might  obscure  or 
completely  suppress  the  entire  extent  of  the  visual  field  of  the 
right  side  (lateral  right  hemiopid}.  Lateral  left  hemiopia 
would  ensue  from  a  lesion  affecting  in  the  same  manner  the 
optic  band  of  the  right  side. 

Thus  speaks  theory ;  as  for  facts,  there  are  numerous  ex- 
amples which  demonstrate  that  lateral  hemiopia  is  really  the 
consequence  of  a  lesion  bearing  upon  one  of  the  optic  bands.1 
The  effect  will  remain  the  same,  no  matter  upon  what  part 
of  the  band,  between  its  origin  in  the  genicular  body  and  its 
termination  in  the  chiasma,  the  lesion  occurs.  Lateral  hemio- 
pia may  also  be  produced  not  only  by  a  lesion  in  the  band 
itself,  but  also  as  a  contiguous  phenomenon  in  consequence 
of  lesions — hemorrhage  or  tumors — developed  in  parts  which 
are  in  more  or  less  immediate  relation  with  the  tract,  such,  for 
example,  as  the  lower  part  of  the  cerebral  peduncle  (pes)  or  in 
the  pulvinar. 

Other  modes  of  hemiopia  are  not  difficult  to  interpret.  A 
lesion,  a  tumor,  for  example,  situated  at  (3),  that  is,  upon  the 
median  part  of  the  chiasma  in  such  way  as  to  involve  only 
the  decussating  optic  fibres  (c,  d)  might  paralyze  the  left 

(1)  half  of  the  retina  of  the  right  eye  as  well  as  the  right  half 

(2)  of  the  retina  of  the  left  eye,  and  so  produce  what  is  called 
temporal   hemiopia.     Saemisch    foretold,    in    a  case   of  this 
kind,  while  the  patient  still  lived,  that  such  was  the  location 
of  the  lesion,  and  autopsy  fully  justified  his  prediction.2 

On  the  contrary,  that  hemiopia,  called  nasal,  characterized 
by  the  suppression  of  the  median  portion  of  the  field  of  vision, 
would  be  produced  if  the  course  of  the  direct  fibres  (a,  b) 
only  were  interrupted,  at  the  chiasma,  for  example,  in  conse- 
quence of  lesions  occupying  each  side  symmetrically  at  the 
points  (4,  4).  This  is  a  combination  which  is  indeed  rare. 
There  exists,  however,  some  examples  ;  among  others  one 


1  See,  among  others,  the  case  of  E.  Miiller  in  the  Arch,   fiir  Ophthalmologie, 
VIII.  Band  i,  S.  160. 
*  See  also  E.  Muller  in  Meissner's  Jahresbericht,  1861,  S.  458. 


CROSSED   AMBLYOPIA.— LATERAL   HEMIOPIA.  99 

carefully  described  by  Knapp.1  In  this  case  it  resulted  from 
a  pressure  upon  the  points  indicated,  by  the  anterior  cerebral 
arteries  and  the  posterior  communicant  artery  enlarged  and 
indurated  by  an  atheromatous  degeneration. 

I  will  dwell  no  longer  upon  these  forms  of  hemiopia,  which 
do  not  at  present  directly  interest  us,  but  return  to  lateral 
hemiopia.  It  seems  an  established  fact  that  this  visual  trouble 
is  the  necessary  result  of  a  lesion  of  the  optic  bands  ;  it  is 
also  generally  affirmed  to  be  the  necessary  consequence  of  a 
lesion  which  may  affect  the  optic  nerve-fibres  beyond  the 
corpora  geniculata  (7)  in  their  deep  intracerebral  tract  (in  8, 
9).  In  my  opinion,  clinical  and  pathological  anatomy  con- 
tradict that  assertion — at  all  events,  when  made  in  too  absolute 
a  manner ;  and  in  this  respect  I  can  but  repeat  that  which  I 
just  now  have  said;  I  do  not  believe  that  there  now  exists 
a  solitary  observation  showing,  beyond  doubt,  the  develop- 
ment of  lateral  hemiopia  in  consequence  of  an  intracerebral 
lesion  outside  of  all  participation  of  the  optic  tracts ,  whereas 
facts  exist  where  a  lesion  of  the  posterior  part  of  the  internal 
capsule,  or  the  foot  of  the  diverging  fibres,  has  produced 
hemianaesthesia,  and  at  the  same  time  crossed  amblyopia,  a 
visual  trouble  very  diverse  from  hemiopia. 

That  being  the  case,  how  can  we  understand,  in  a  sche- 
matic view,  that  effect  of  a  cerebral  lesion,  while  at  the  same 
time  we  recognize  the  incontestable  fact  of  hemiopia  being 
the  consequence  of  a  lesion  of  the  optic  bands  ? 

To  this  end  a  slight  modification  of  the  common  scheme 
will  suffice.  It  is  generally  admitted  that  the  nerve-fibres 
coming  from  the  right  eye  and  the  left  eye  which  compose 
each  of  the  optic  bands  continue  their  course  beyond  the 
corpora  geniculata  uninterruptedly  into  the  very  depths  of  the 
corresponding  hemispheres,  and  that  view  accords  with  the 
prevailing  idea  that  a  lesion  of  the  optic  nerve-fibres  in  their 
intracerebral  course  is  equivalent  to  a  lesion  of  the  optic 
bands,  and  consequently  produces  hemiopia. 

I  propose  to  admit,  on  the  contrary,  that  only  the  fasciculi 

1  Arch,  of  Scientific  and  Practical  Medicine,  1873,  p.  293. 


100  DISEASES   OF  THE   BRAIN. 

of  the  bands  which  decussate  in  the  chiasma  (c,  d)  reach  their 
profound  depths,  whatever  they  may  be,  without  new  decus- 
sation  ;  whereas  the  direct  fasciculi  do  completely  decussate 
beyond  the  corpora  geniculata,  before  entering  into  the 
depth  of  the  hemispheres  (8,  9)  ;  this  occurs  upon  an  undeter- 
mined point  of  the  median  line,  perhaps  in  the  tubercula 
quadrigemina.  From  that  arrangement  it  would  result  that 
the  fasciculi  (b,  d),  reunited,  for  example,  in  a  point  of  the 
left  hemisphere  (8),  would  represent  the  totality  of  the  fibres 
coming  from  the  retina  of  the  right  eye,  and  that  the  fasciculi 
(a,  c)  would  represent  the  totality  of  fibres  coming  from  the 
left  eye.  The  optic  fibres,  according  to  that,  in  their  pro- 
found course,  are  at  length  all  reduced  to  the  type  of  com- 
plete decussating  fibres,  and  one  can  comprehend  that,  in  an 
apparatus  so  constructed,  a  lesion  of  the  optic  bands  would 
produce  lateral  hemiopia,  although  a  lesion  situated  deeply 
in  the  substance  of  the  brain  would  to  the  contrary  produce 
crossed  amblyopia. 

I  give  you  this  hypothesis  for  whatever  it  is  worth.  At 
present  it  has  no  anatomical  base.  But  at  all  events  it  fur- 
nishes, if  I  am  not  deceived,  an  easy  means  of  very  simply 
representing  the  tolerably  complex  facts  revealed  by  clinical 
observation. 


ELEVENTH  LECTURE. 

ORIGIN   OF   THE   CEREBRAL   PORTION   OF   THE   OPTIC 

NERVES. 

Summary :— Relations  of  Crossed  Amblyopia  and  Sensitive  Hcmi- 
aneesthesia,  Resulting  from  a  Lesion  of  Hie  Internal  Capsule. — 
Cerebral  Origin  of  the  Optic  Nerves.— Diverging  Fibres  of  Reil.— 
Radiating  Cortico-optic  Fasciculi. — Anterior  Fibres  (Anterior  Roots 
of  the  Thalami  Optici) ;  Middle  Fibres  (Lateral  Expansion) ;  Poste- 
rior Fibres  (Cerebral  Expansion  of  the  Optic  Nerves) ;  Anatomical 
Relations  between  the  Cerebral  Expansion  of  the  Optic  Nerves  and 
the  Centripetal  Portions  of  the  Radiating  Fibres  (Sensitive  Hemi. 
anaesthesia).— Optic  Bands.— Origin  of  the  External  Root  (Thalami 
Optici);  External  Genicnlate  Bodies,  Anterior  Tubercula  Quadri- 
gemina.— Origins  of  the  Internal  Root  (Internal  Genicnlate  Bodies, 
Posterior  Tubercula  Q,uadrigeinina). — Relation  between  the  Mass 
of  Gray  Substance  and  the  Gray  Cortex  of  the  Encephalon.— Cortico- 
optic  Radiating  Fasciculi. — Effects  of  Lesions  of  the  Anterior  Tu- 
bercnla  Q,uadr igemina.— Facts  of  Lateral  Hemiopia  of  Supposed 
Intra-cerebral  Origin. 

GENTLEMEN  : 

I  hope  that  I  have  demonstrated  the  existence  of  crossed 
amblyopia  as  a  symptom  of  lesion  in  the  posterior  part  of  the 
internal  capsule,  or  of  the  corresponding  irradiations  of  the 
foot  of  the  diverging  fibres. 

At  the  same  time  I  have  attempted  to  prove  de  Graefe's 
proposition,  that  homologous  hemiopia  might  be  (crossed 
amblyopia  excluded)  the  only  functional  trouble  of  vision 
following  a  lesion  of  the  cerebral  hemispheres,  to  be  at  least 
too  sweeping,  and  that  the  arguments  upon  which  it  rests 
ought  to  be  completely  revised. 

I  now  wish  to  examine  whether  normal  anatomy  can  ex- 
plain why  the  sensorial  trouble  in  question,  that  is,  crossed 
amblyopia,  is  a  frequent,  as  it  were  habitual,  accompaniment 


102  DISEASES   OF  THE   BRAIN. 

of  sensitive  hemianaesthesia  resulting  from  a  lesion  of  the  in- 
ternal capsule. 

This  hemianaesthesia  of  common  sensibility,  you  remember, 
may  be  produced  through  the  existence  of  a  fasciculus  of 
direct  centripetal  fibres,  that  is,  fibres  not  stopping  in  the 
gray  ganglia  of  the  central  masses,  and  which,  upon  issuing 
from  the  internal  capsule,  form  the  very  posterior  portion  of 
the  diverging  fibres. 

Does  there  exist  a  connection,  a  more  or  less  immediate 
relation,  between  that  sensitive  fasciculus  and  the  sensorial 
fasciculi  designed  to  put  the  apparatus  of  vision  in  communica- 
tion with  the  gray  cortex  of  the  brain  ?  To  enter  upon  this 
question  it  is  first  necessary  to  study  the  origin  of  the  pro- 
found or  cerebral  part  of  the  optic  nerves.  We  will  examine 
this  difficult  subject,  which  is  still  obscure  in  more  than  one 
point.  I  must  not,  however,  omit  giving  you  the  principal 
outlines,  if  only  to  indicate  the  direction  in  which  our  future 
researches  should  be  made,  and  where  pathological  anatomy 
will  very  likely  be  called  to  play  a  dominant  part. 

According  to  the  general  plan,  the  encephalic  nerves  ought 
to  encounter,  before  penetrating  the  brain  itself,  one  or  more 
masses  of  gray  substance,  Avhich  it  is  agreed  to  call  the  gan- 
glions of  origin,  and  the  expansions  arising  from  these  ganglia 
put  these  nerves  in  an  indirect  rapport  with  the  gray  cortex 
of  the  cerebral  hemispheres. 

A  priori,  there  is  nothing  to  induce  belief  that  the  optic 
nerves  escape  the  rule.  In  fact,  they  do  not  escape  it,  but 
their  distributions  are  very  complicated  and  ill-known,  espe- 
cially in  some  of  the  details. 

I.  I  will  pause  an  instant  to  note  the  construction  of  a  por- 
tion of  the  diverging  fibres  of  Reil.1 

1  The  various  fasciculi,  peduncular  or  otherwise,  which  form  the  diverging  fibres, 
(fibres  convergentes  of  Luys)  (systZme  de projection  de  ir  ordre  of  Meynert)  com- 
pose the  greater  portion  of  the  white  central  mass  called  centrum  ovale,  which  the 
gray  cortex  of  the  hemispheres  envelops  and  encloses  like  a  purse.  They,  how- 
ever, do  not  represent  the  totality  of  that  mass.  It  contains,  beyond  these,  fasci- 
culi entirely  foreign  to  the  preceding,  but  which  mix  with  them.  These  last  fasci- 
culi constitute  that  which  Meynert  calls  the  system  of  association.  One  may 
distinguish  in  a  general  way  the  two  orders  of  fasciculi  which  compose  this  system. 


CEREBRAL  PORTION   OF  THE   OPTIC   NERVES. 


103 


In   the  scheme  which  I  present  to  you  and  which  is  bor- 
rowed from  Huguenin  (loc.  cit. ,  pi.  69,  page  93),  the  ablation 


Ltoflent.nudeus., 

PiLeis  uniting  two  convols,  i       T     .!    . 

a*1)  j       Fasjculus  arcuattis. 


Tasicrulu^  JongiUid.in£ ' 

Pulvfnar.'''        ;      / 
Horn  of  Ammok  / 

ExLeriLCorpora  geniculata'.    *».•/."    'aL^  ., 

Pos't.horn  of  -latyentricle. 

Caniatedextr.  of.  corpus  slriat'um. 


FIG.  30. — Antero-posterior  section  of  a  monkey's  brain  (Cercocebus  cinomolgus} 
showing  the  connecting  fibres  of  the  brain. — (Meynert,  Strieker's  Hand-book.) 

of  the  superior  parts  of  the  hemispheres,  including  the  corpus 
callosum,  has  laid   bare  the  ventricular  cavities.     You   will 


One  kind  consists  of  commissures  which  unite  the  homologous  parts  of  the  two 
hemispheres.  Such,  for  example,  are  the  corpora  callosa  and  the  anterior  com- 
missure. The  others  are  composed  of  fibres  having  a  general  antero-posterior 
direction,  which  bring  into  relation  the  various  points  of  the  same  hemisphere. 
Fig.  30,  borrowed  from  Meynert  (loc.  cit.,  Fig.  233),  representing  the  anterior 
section  of  the  brain  of  a  monkey  {Cercocebus  cinomolgus],  very  well  exhibits  the 
direction  of  the  principal  fasciculi  of  the  antero-posterior  system  of  association. 
There  are  to  be  seen  the  fibres  uniting  two  convolutions  (fibra  proprice),  well 
described  by  Gratiolet,  the  fasciculus  arcuatus,  the  fibres  of  which  extend  beneath 
the  corpus  callosum  from  the  occipital  to  the  frontal  lobe  ;  the  inferior  longitudinal 
fasciculus  which  joins  the  occipital  lobe  to  the  extremity  of  the  sphenoidal  lobe,  and 
finally,  the  fasciculus  uncinatus,  which  runs  nearly  vertical  and  which  joins  the 
frontal  to  the  sphenoidal  lobe. 


104 


DISEASES   OF  THE   BRAIN. 


notice  particularly  the  inferior  part,  or  the  posterior  cornu  of 
the  ventricle  which  here  plays  an  important  role  in  topogra- 
phy (Fig.  32). 


Fibres  of  optic  thalamus 
extending  to  the  periphery 


Caudated  nucleus 


Fibres  of  caudated  nucleus 
extending  to\ the- periphery 


Direct 
fibres. 


••§ 


FIG.  31. — Scheme  illustrative  of  the  different  orders  of  peduncular  fibres. — (Hugue- 
nin.) 

The  caudated  ganglion  has  been  detached  and  its  outlines 
are  represented  by  a  dotted  line  ;  its  diverging  fibres,  that  is 


CEREBRAL  PORTION  OF  THE  OPTIC  NERVES.     10$ 

to  say,  the  plane  of  the  cortico-striated  radiating  fibres,  have 
also  been  removed.  Thus  is  uncovered  the  plane  of  the  cor- 
tico-optic  radiating  fibres.  In  these  last  fasciculi  it  is  possible 
to  distinguish  three  groups  of  fibres  :  1st,  the  anterior  ones 
called  anterior  roots  of  the  thalami-optici  (Vordere  Stiel),  they 
are  directed  towards  the  frontal  regions  ;  2d,  others  are  mid- 
dle or  lateral  ;  3d,  and  finally,  the  posterior  ones  are  desig- 
nated by  Gratiolet,  who  first1  well  studied  them,  under  the 
name  of  optic  cerebral  expansions,  or  expansion  of  the  optic 
nerves  (Sehstrahlungen).  The  fasciculi  of  the  last  group, 
which  are  the  special  object  of  our  study,  are  separated  from 
the  cavity  of  the  posterior  cornu  only  by  the  ependymus  and 
the  tapetum,  a  special  expansion  of  the  splenium  of  the  corpus 
callosum. 

It  is  in  this  same  region,  but  on  a  deeper  plane,  that  the 
cerebral  expansions  of  the  fasciculi  of  centripetal  fibres  are 
spread,  the  lesion  of  which  produces  sensitive  hemianaesthe- 
sia  of  cerebral  origin.  There  exists,  then,  a  relation  of  pro- 
pinquity, of  contiguity,  between  these  fasciculi  and  the  optic 
expansions,  and  that  relation  would  well  explain  anatomi- 
cally the  frequent  coexistence  of  hemiansesthesia  and  crossed 
amblyopia  if  it  could  be  well  established  that  those  fasciculi 
which  bear  the  name  of  optic  expansions  are  really  a  more  or 
less  direct  prolongation  of  the  optic  nerves. 

II.  We  will  make  a  little  digression  upon  this  point  in 
order  to  ascertain  what  is  known  about  the  gray  ganglia  at 
the  base  of  the  encephalon,  outside  of  the  brain  proper,  where 
the  optic  nerves  originate. 

Here  it  seems  proper  to  examine  the  exterior  architecture 
of  the  parts  which  we  are  about  to  consider. 

After  detaching  the  entire  isthmus  from  the  encephalon, 
leaving  attached  the  thalami  optici,  an  examination  of  the 
posterior  face  of  the  preparation  thus  obtained  will  discover 
as  follows  :  1st,  anteriorly,  on  each  side,  are  the  thalami  op- 
tici, which  separate  the  third  ventricles  ;  2d,  posteriorly,  the 

1  See  Gratiolet,  Anat.  comparee,  t.  II.,  p.  181  et  suiv.    Luys,  loc.  cit.,  p.  173. 


io6 


DISEASES   OF   THE   BRAIN. 


tubercula  quadrigemina,  both  anterior  and  posterior  ;  3d, 
externally,  the  anterior  conjunctive  fibres  connecting  by  their 
internal  extremities  with  the  anterior  tubercula  quadrigemina, 


^l(.TQOl  Of 

^  Optic  thaJamiis , 


Corpus, 
striatuiri 


Arch,  and 
three  pillars' 


ions 


Corpora"? 
quadrigemma 

Horn  of  Ammon' 
JEbst-liom  of  la 


-^  of 

Gratiolet.  (optic) 


FIG.  32. — Radiations  from  the  thalamus  opticus. — (Huguenin.) 


the  posterior  conjunctive  fibres  connecting  with  the  posterior 
tubercula  quadrigemina.  Then,  in  the  same  region,  by  raising 
the  posterior  extremity  of  the  thalami  optici,  or  pulvinar, 
may  be  seen,  internally,  the  internal  geniculate  body,  and  ex- 


CEREBRAL  PORTION  OF  THE  OPTIC  NERVES.     IO/ 

ternally,  a  gray  mass,  somewhat  more  voluminous,  which  is 
the  external  geniculate  body. 

Behind  and  above  these  parts  are  to  be  seen  the  loop  of 
Reil,  the  processus  cerebelli  ad  testes,  the  cerebral  pedun- 
cles, the  restiform  bodies,  and  the  middle  cerebral  pedun- 
cles. 

The  internal  and  external  geniculate  bodies  are  notably  the 
first  two  ganglia  of  gray  substance  with  which  the  optic  nerves 
enter  into  rapport  on  their  way  to  the  encephalon.  The  optic 
nerves  posterior  to  the  chiasma  take  the  name  of  optic  tracts, 
or  optic  bands,  and  in  the  posterior  two-thirds  they  are  divided 
into  two  tracts  which  may  be  considered  as  roots,  the  one 
internal,  the  other  external. 

The  external  is  most  voluminous  and  also  most  important. 
It  furnishes  several  fibres  which  run  to  various  gray  ganglia. 
1st.  There  can  be  seen  a  fasciculus  which  goes  to  the  external 
geniculate  body.  These  bodies  are  a  tolerably  voluminous 
mass  of  gray  substance,  enclosing  ganglionic  cells,  stellate  or 
fusiform,  of  considerable  dimensions,  and  which  are  to  be 
found  well  represented  in  the  work  of  Henle  (Fig.  177,  p. 
249).  2d.  A  second  fasciculus,  situated  within  the  preceding, 
enters  the  inferior  portion  of  the  thalamns  about  twelve  milli- 
metres anterior  to  the  extremity  of  the  pulvinar.  Upon  a 
transverse  section,  such  as  is  represented  in  the  work  of  Mey- 
nert  (Fig.  249,  II.  R.),  the  fasciculus  in  question  is  situated 
between  the  external  geniculate  body  and  the  foot  of  the 
peduncle.  The  existence  of  this  fasciculus,  affirmed  by 
Gratiolet,  is  also  very  explicitly  recognized  by  Meynert, 
Henle,  and  Huguenin.  3d.  A  third  fasciculus  which,  accord- 
ing to  Gratiolet,  should  be  the  most  apparent  and  best  known 
of  the  roots  of  the  optic  nerves,  winds  around  the  external 
geniculate  bodies  and  enters  the  anterior  tuberculum  quadri- 
geminus  of  the  corresponding  side.1  The  description  which 
Gratiolet  has  given  of  this,  confirmed  also  by  Vulpian  and 
Huguenin,2  is  perfectly  exact  as  concerns  the  most  of  mam- 


1  Gratiolet,  loc.  cit.,  p.  180. 

2  Huguenin,  WestphalPs  Arch.,  V.  Bd.,  ist  Heft,  2d  Heft,  1875. 


108  DISEASES   OF  THE  BRAIN. 

mifera.1  It  does  not  hold  true  in  the  same  degree  for  the 
monkey;  and  in  man,  though  the  fasciculus  exists,  it  can  be 
anatomically  demonstrated  only  by  great  care.2 

It  is  thus  seen  that  the  external  roots  of  the  optic  nerves 
take  their  origin  in  three  ganglia  of  gray  substance,  to  wit : 
1st,  the  thalami  optici ;  2d,  the  external  geniculate  bodies  ; 
3d,  the  anterior  tubercula  quadrigemina  (nates).  Such  cer- 
tainly are  the  principal  sources  of  the  optic  nerves  in  man, 
and  with  a  great  number  of  animals  they  are  probably  the 
only  ones  ;  at  least  this  seems  to  be  established  by  the  inter- 
esting experiments  of  Gudden,3  consisting  of  the  extirpation 
of  the  eyeballs  of  very  young  rabbits.  In  the  animals  thus 
operated  upon,  when  killed  some  months  thereafter,  it  was 
observed  that  consecutive  atrophy  had  ensued  in  the  central 
parts  upon  the  anterior  tubercula  quadrigemina  (nates),  the 
thalami  optici,  and  the  external  geniculate  bodies  ;  on  the 
other  hand,  the  posterior  tubercula  quadrigemina  (testes)  and 
the  internal  geniculate  bodies  did  not  participate  in  the  atrophy. 

The  internal  roots,  though  less  important  than  the  external, 
should  not  be  neglected,  especially  when  relating  to  man. 
You  know  that  they  are  connected  with  the  internal  geniculate 
bodies.  These  internal  geniculate  bodies  contain  only  rudi- 
mentary nerve-cells  (Henle),  and  consequently  cannot  be 
considered  as  a  centre  in  the  same  sense  as  can  the  external 
geniculate  bodies.  The  nerve-fasciculi  of  the  internal  root,  it 
may  be  either  after  traversing  the  geniculate  bodies,  or  by  a 
direct  course,  proceed  to  a  final  termination  at  the  anterior 
tubercula  quadrigemina  (nates). 

Quite  recently  Huguenin  (Arch,  fur  Psychiatrie,  1875,  V. 
Bd.,  Fasc.  .2,  p.  344)  has  maintained  that  the  internal  roots  of 

1  For  brains  of  the  rabbit  and  dog,  see  plate,  Gudden's  work  (Arch,  of  Ophthal., 
XX.,  1875) ;  for  brain  of  cat,  the  plates  of  Forel  (Beitrage  zur  Kenntniss  der 
Thalamus  Opticus).  Sitzbericht.  der  k.  Akad.,  LXVI.  Bd.,  1872,  T.  II., 
Fig.  10. 

8  A  fourth  fasciculus,  situated  outside  of  the  one  which  stops  in  the  external  genic- 
ulate body,  is  spread  upon  the  thalamus  and  takes  part  in  forming  the  Stratum 
zonale.  Previously  indicated  by  Arnold  and  Gratiolet,  this  fasciculus  is  described 
and  represented  also  by  Meynert,  p.  436. 

8  Gudden.— Arch,  fur  Ophthalmol.,  XX. 


CEREBRAL  PORTION   OF  THE   OPTIC   NERVES.          109 

the  optic  nerves,  in  man  at  least,  are  in  anatomical  rapport 
with  the  posterior  tubercula  quadrigemina,  either  directly 
or  by  the  intermediation  of  the  internal  geniculate  bodies. 
According  to  that,  the  posterior  tubercula  quadrigemina 
could  not,  in  man,  be  excluded,  as  it  seems  to  be  in  animals, 
from  the  apparatus  of  the  optic  nerves.  This  is  not  in  con- 
tradiction with  the  teaching  of  certain  facts  concerning  gray 
tabetic  induration  of  the  optic  nerves.  Quite  recently,  in  an 
ataxied  woman — blind  for  fifteen  years — gray  induration  of 
the  optic  nerves  could  be  followed  beyond  the  chiasma  along 
the  optic  bands  quite  to  the  geniculate  bodies.  The  tuber- 
cula quadrigemina,  the  anterior  (nates),  as  well  as  the  pos- 
terior (testes),  had  very  nearly  retained  the  white  color  of  the 
normal  state,  but  they  both  were  manifestly  reduced  in  size 
(case  of  Magdaliat1).  I  have  observed  several  cases,  all  sim- 
ilar to  the  preceding. 

We  must  now  examine  how  the  various  masses  of  gray 
substance  which  have  been  enumerated  are  brought  into 
relation  with  the  gray  cortex  of  the  encephalon.  The  con- 
nection is  established,  as  I  have  shown,  by  a  system  of  fibres 
which  constitute  the  most  posterior  portion  of  the  radiations 
of  the  thalami  optici  (cortico-optic  diverging  fasciculi),  and 
which  are  sometimes  called  the  optic  radiations  of  Gratiolet. 
You  can  follow  these  somewhat  complex  anatomical  details 
in  the  following  plate,  which  I  borrow  from  the  work  of  Mey- 
nert,  and  which  represents  the  brain  of  a  monkey  (Cercocebus 
cinomolgus]  (Fig.  33). 

It  can  there  be  seen  how  the  fasciculi  of  fibres,  or  radiations, 
leaving  the  external  geniculate  bodies,  the  internal  geniculate 
bodies,  the  pulvinar,  and  the  anterior  tubercula  quadrigem- 
ina (these  last  by  the  intermediation  of  the  anterior  con- 
junctive arms),  go  by  a  recurrent  way  to  associate  with  a 
medullary  fasciculus  which  is  only  a  collection  of  the  direct 
peduncular  centripetal  fibres  that  we  have  already  described 
(Lectures  VIII.  and  IX.,  Fig.  26),  and  upon  which  the  com- 
mon sensibility  of  the  opposite  side  of  the  body  depends. 

1  The  anterior  and  posterior  conjunctive  arms  were  remarkably  atrophied ;  they 
had  a  heavy  white  color,  a  little  tinted  with  yellow. 


no 


DISEASES   OF  THE   BRAIN. 


With  that  collection  of  fibres  are  doubtless  mingled  other 
fibres  coming  from  the  olfactive  tract  by  way  of  the  anterior 
commissure,  the  extremities  of  which,  according  to  the  de- 
scriptions of  Burdach  and  Gratiolet,  are  directed  posteriorly 

Denial  extremity. 


Ertfrance  of 
fiss.of  Srlvius. 


Segments'  of 
lentic.  nucleus. 

'orpus  callosutn. 

ueue  of  caudated 
"nucleus  , 

Ant.  horn  o£ 
lat.  ventricle, 

•Septum  lucid  _  . 
.Crus  cerebri.  (foot) 
Ant  .commissure. 

ddle  ventricle, 
ddle  commissure^ 

.ddle  ventricle. 

Optic  thalamus^ 
'.to  corp,  genie. 

rpus  callosum. 


«  Corpora 


JM&\ 

Corpora  quadr.  extern. 
Corpora  quadrigemina 

Horn  of/ 


Post.iiom.ofLatVent. 
tic  thalamug. 


Occipital  region, 


FIG.  33.  —  Antero-posterior  horizontal  section  of  the  left  hemisphere  of  a  monkey's 
brain  ((Jercocebus  cino  molgus}.  —  (Meynert,  Strieker's  Handbook.) 

into  the  substance  of  the  occipital  and  sphenoidal  lobes. 
Clinical  facts  lead  to  the  belief  that  there  also  are  mingled 
decussating  nerve-fibres  connected  with  the  auditory  and 
gustatory  nerves.  If  that  arrangement,  now  altogether  hy- 
pothetical, should  come  to  be  anatomically  verified,  it  can 


CEREBRAL  PORTION   OF  THE   OPTIC   NERVES.  Ill 

be  understood  how  crossed  obscuration  of  the  smell,  taste, 
and  hearing  should,  in  the  same  manner  as  amblyopia,  be  an 
ordinary  symptom  of  cerebral  hemiancssthesia^ 

The  encephalic  region  to  which  I  have  drawn  your  atten- 
tion, and  which  responds  to  the  most  posterior  part  of  the 
foot  of  the  radiating  fibres  (couronne  rayonnante),  may  be 
considered,  then,  as  a  highway  where,  in  the  depths  of  the  en- 
cephalon,  are  encountered,  within  a  very  narrow  space,  all  the 
sensitive  and  sensorial  lines  of  travel.  This  is  a  highway  ; 
it  is  not  a  centre.  The  cerebral  centre,  properly  speaking, 
should  be  sought  in  the  prolongations  of  the  medullary  fibres, 
in  the  gray  cortex  of  the  occipital  and  sphenoidal  lobes. 

We  shall  return  to  this  point  in  connection  with  localiza- 
tions in  the  cortical  system. 

III.  You  might  have  observed  in  the  preceding  anatomical 
expose  that  the  tubercula  quadrigemina  seem  to  furnish  the 
only  point  where  the  fasciculi  of  the  optic  nerves,  after  their 
decussation  in  the  chiasma,  again  approach  each  other  upon 
the  median  line.  This  is  the  point  where  that  supplementary 
decussation  is  effected,  which,  according  to  my  hypothesis, 
would  reduce  the  optic  nerve  to  the  same  footing  as  other 
nerves.  That  is  a  question  which  at  present  seems  difficult 
to  resolve  by  exclusively  anatomical  means.  Upon  the 
median  line,  between  the  tubercula  quadrigemina,  numerous 
decussations  of  fibres  are  without  doubt  anatomically  demon- 
strated. But  it  cannot  be  decided  whether  these  decussated 
fibres  are  really  in  connection  with  the  optic  nerves,  and  es- 
pecially whether  they  are  the  prolongations  of  optic  fibres 
non-decussating  in  the  chiasma.  Experimentation,  and  above 
all  pathological  anatomy,  should  certainly  have  the  first  place 
in  the  solution  of  this  question.  The  experiments  of  Flou- 
rens  have  already  shown  that  with  mammifera  and  with  birds, 
the  ablation  of  the  optic  tubercles  produce  amblyopia  or 
crossed  amaurosis.  But  this  is  with  animals  in  which  the 

1  According  to  the  theory,  cerebral  hemiansesthesias  should  be  distinguished 
from  those  dependent  upon  a  lesion  of  the  protuberance  or  the  cerebral  peduncles 
(crus  cerebri)  by  non-participation  in  the  last  case  of  vision  or  smell. 


112  DISEASES   OF  THE  BRAIN. 

ocular  axes  are  directed  externally  and  in  which  the  decus- 
sation  in  the  chiasma  is  doubtless  complete. 

With  man  the  elements  for  the  solution  of  the  problem  are 
as  yet  defective.  With  him  lesions  of  the  tubercula  quadri- 
gemina  are  not  rare,  but  they  ordinarily  are  bilateral,  and 
consequently  producing  bilateral  blindness,  they  can  prove 
nothing.  In  fact,  it  is  still  a  question  whether  lesions  of  the 
anterior  tubercula  quadrigemina  will,  like  a  lesion  of  the  optic 
bands,  produce  lateral  hemiopia,  or  if,  on  the  contrary,  they 
will  produce  crossed  amblyopia,  as  would  be  in  keeping  with 
my  hypothesis.  In  favor  of  my  hypothesis,  I  can  as  yet  cite 
but  one  case,  reported  by  Dr.  Bastian,  and  in  which  a  unilat- 
eral lesion  of  the  anterior  tubercula  quadrigemina  had  pro- 
duced crossed  amblyopia. 

But  that  fact  is  at  present  the  only  one,  and  besides  it  is 
related  with  too  little  detail  to  be  received  as  decisive.1 

IV.  It  remains  to  ascertain  if  crossed  amblyopia  is  the 
only  kind  of  functional  trouble  of  the  vision  which  can  be 
produced  by  a  lesion  of  the  brain  proper,  or  if,  on  the  con- 
trary, hemiopia  may  not  also  follow  as  a  consequence  of  cer- 
tain pathological  localizations  in  the  hemisphere.  That  is  a 
point  which,  I  think,  no  one  is  at  present  competent  to  de- 
cide. I  incline,  however,  in  the  absence  of  contradictory 
autopsies,  to  believe  that  in  most  instances  of  hemiopia 
which  have  been  ascribed  to  a  lesion  of  the  brain,  the  lesion 
has  either  not  occupied  the  deep  regions  of  the  hemisphere, 
or  that  it  has  extended  to  the  basilar  portions  in  such  manner 
as  to  involve  more  or  less  directly  one  or  the  other  of  the 
optic  bands. 

To  show  that  deep  lesions  of  the  brain  produce  hemiopia — 
lateral  hemiopia — cases  are  specially  cited  where  the  visual 
disturbance  is  suddenly  developed  upon  an  apoplectic  stroke, 
and  where,  at  the  same  time,  the  limbs  of  one  side  are  affected 
with  motor  hemiplegia,  and  sometimes  also  with  anaesthesia. 
Nothing  is  better  established  in  clinic  than  facts  of  this  kind, 

1  H.  C.  Bastian,  The  Lancet,  1874,  25th  July. 


CEREBRAL   PORTION   OF  THE   OPTIC   NERVES.  113 

of  which  Schoen,  quite  recently,  in  an  interesting  work,  has 
cited  several  examples.1  But  the  conduction  of  the  autopsies 
have  to  the  present  been  faulty,  and  it  may  be  queried  if  the 
lesion  found  in  these  cases  occupied  really  the  deep  brain,  or, 
on  the  contrary,  the  base  of  the  encephalon.  It  seems  estab- 
lished, you  have  not  forgotten,  that  destruction  or  compres- 
sion of  one  of  the  optic  bands  produces  lateral  hemiopia  ;  and, 
on  the  other  hand,  the  anatomical  relation  which  exists  be- 
tween the  bands  and  certain  parts  of  the  isthmus,  such, 
among  others,  as  the  crura  cerebri,  is  well  known.  Such 
being  the  case,  it  could  not  be  otherwise  than  that  a  lesion 
properly  localized,  as,  for  example,  in  a  crus  cerebri,  might 
result  in  producing  at  the  same  time  lateral  hemiopia  and 
motor  hemiplegia,  and  perhaps  also  hemianaesthesia.  Hem- 
orrhage, suddenly  developed  in  the  substance  of  the  pos- 
terior part  of  the  thalami  optici,  might,  as  can  be  understood, 
be  followed  with  the  same  effect.  It  is  evident  that  these 
diverse  combinations  are  only  phenomena  of  propinquity. 

In  any  case,  it  should  be  known  that  among  instances 
which  have  been  reported  of  lateral  hemiopia  of  supposed 
intracerebral  origin,  there  are  a  certain  number  which  in  some 
respects  do  not  conform  to  the  interpretations  that  I  have 
proposed.  Such,  among  others,  are  those  where  right  lateral 
hemiopia  develops  itself  in  concert  with  aphasia,  and  some- 
times also  with  various  modifications  of  the  sensibility  or 
motion  of  the  limbs  of  the  right  side  of  the  body.2 

These  facts  do  not  constitute  a  homogeneous  group  ;  the 
first  category  includes  a  form  peculiar  to  migraine ,3  that  is, 
symptoms  essentially  transitory,  returning  by  accesses,  and 
above  all  marked  by  scintillations,  vertigo,  more  or  less 
marked  lateral  hemiopia,  and  sometimes  also  with  a  certain 

1  Arch,  der  Heilkunde,  p.  19,  1875. 

2  Various  cases  of  this  kind  have  recently  been  related  by  Bernhardt  (Berliner 
klin.  Wochen.,  32,  1872,  and  Centralblatt,  1872,  39),  and  by  Schoen  (loc.  cit.). 
See  also  H.  Jackson,  A  Case  of  Hemiopia  with  Hemianaesthesia  and  Hemiplegia, 
in  the  Lancet,  Aug.  29,  1874,  p.  306. 

3  See  respecting  this  form  of  migraine  the  works  of  Tissot,  Labarraque,  Piorry, 
and  Latham  (on  Nervous  Sick  Headache,  Cambridge,  1873),  and  above  all  the  re- 
cent work  of  Ed.  Liveing  (on  Megrim,  etc.,  London,  1873). 

8 


114  DISEASES   OF   THE   BRAIN. 

degree  of  aphasia  and  numbness  in  the  face  and  limbs  of  the 
right  side.  Headache,  nausea,  and  vomiting  usually  end  the 
attack.  It  is  clear  that  these  cases  cannot  be  ascribed  to  a 
durable,  material  alteration.  It  is  not  thus  with  the  cases  of 
the  second  category,  where  the  concurrence  of  aphasia,  hemi- 
plegia,  and  hemiopia- remain  permanent.1 

At  present  I  do  not  see  how  these  various  cases,  revealed 
by  clinic,  can  be  anatomically  explained  upon  the  hypothesis 
of  a  single  lesion.  I  can  only  call  attention  to  the  difficulties, 
the  solution  of  which  is  reserved  to  the  future. 

1  It  can  be  understood  that  a  voluminous  tumor  might  produce  all  the  results 
noted  in  both  categories,  and  it  has  happened  in  a  case  recently  published  by 
Hirschberg  in  the  Archives  of  Virchow  (Virchow's  Arch.,  T.  65,  I  Heft,  p.  116). 
This  patient  had,  besides  very  characteristic  right  lateral  hemiopia,  aphasia,  and 
hemiplegia  of  the  right  limbs.     Upon  autopsy  there  was  found  in  the  substance  of 
the  left  frontal  lobe,  a  tumor  the  size  of  an  apple,  of  the  kind  called  vascular 
glioma.     The  optic  tract  of  the  left  side  was  very  flattened.     The  views  enter- 
tained in  the  present  chapter  find  a  confirmation  in  that  fact,  since  the  hemiopia 
there  noted  may  belong  to  compression  of  the  optic  tract, 


TWELFTH  LECTURE. 

SECONDARY   DEGENERATION. 

Summary  : — Anterior  or  Lenticulo-Striatcd  Region  of  the  Central  Masses 
(Anterior  Two-thirds  of  Internal  Capsule,  the  Caudated  and 
Lenticular  Ganglia). — Influence  of  Lesions  in  these  Regions  upon 
the  Production  of  Motor  Hemiplegia. — Experimental  Facts. — Accord 
"between  these  and  the  Facts  of  Human  Pathology. — Difference 
between  the  Lesions  of  the  Caudated  Ganglion  and  those  of  the 
Anterior  Part  of  the  Internal  Capsule— Secondary  Degenerations, 
or  Descending  Scleroses. — Lesions  which  Produce  them;  Impor- 
tance of  the  Locality  and  Extent  of  these  Lesions.— Characteristics 
of  Descending  Scleroses  ;  Extent;  Appearance  of  the  Lesion  upon  the 
Crus  Cerebri,  the  Protuberance,  the  Anterior  Pyramid,  and  the  Lat- 
eral Fasciculus  of  the  Spinal  Cord. — Analogies  and  Differences  be- 
tween Lateral  Sclerosis  from  Cerebral  Cause,  and  Primitive  Fascicu- 
lated Sclerosis  of  the  Lateral  Fasciculi.— Symptoms  Belonging  to  Sec- 
ondary Sclerosis  ;  Motor  Impotency,  Permanent  Contractions. — Mus- 
cular Atrophy  Produced  by  Extension  of  the  Lateral  Sclerosis  to  the 
Cornua  of  the  Gray  Substance.— Descending  Sclerosis  Following 
a  Lesion  of  the  Cortex. — Demonstration  of  the  Direct  Peduncular 
Fibres  ;  Anatomico-Pathological  Facts.— The  Locations  of  Cortical 
Lesions  which  Produce  Secondary  Degenerations  Correspond  to 
the  Locations  of  Centres  called  Psycho.Motor. 

GENTLEMEN  : 

We  must  again  turn  to  the  anterior  regions  of  the  central 
masses,  for  the  purpose  of  studying  more  carefully  the  ana- 
tomical and  pathologico-physiological  effects  of  lesions  occur- 
ring in  that  locality. 

That  region,  which  may  be  called  the  lenticulo-striated,  in 
contradistinction  to  the  posterior  or  lenticulo- optic  region, 
embraces,  you  remember,  1st,  the  anterior  two-thirds  of  the 
white  tract  called  the  internal  capsule  ;  2d,  internally  from 
this,  the  large  extremity  or  head  of  the  caudated  ganglion  ; 
3d,  outside,  by  the  side  of  the  island  of  Reil,  the  anterior  two- 
thirds  nearly  of  the  lenticulate  ganglion. 


DISEASES   OF  THE  BRAIN. 


Observation,  and  that  many  times  repeated,  demonstrates 
as  I  have  already  remarked  in  the  course  of  these  lectures 
Lectures  VIII.  and  IX.,  pp.  70  and  71),  that  common  motor 
hemiplegia,  unaccompanied  by  derangement  of  sensibility,  is 
the  almost  inevitable  consequence  of  even  the  smallest  lesions 
occurring  in  the  various  parts  which  I  have  enumerated, 
provided  always  that  the  lesions  in  question  produce  the  de- 


Corpus/^     r  ** 
callosum-iv^-" '      ^ 


Chalamus 


FIG.  34. — An  old  softening  of  the  middle  portion  of  the  caudated  ganglion  and  the 
internal  capsule.     (Right side.) 

struction  or  the  sudden  compression  of  the  nerve -elements  of 
the  affected  area,  instead  of  merely  a  slowly  effected  dis- 
placement, as  is  often  seen  in  the  case  of  tumors. 

I  called  attention  to  an  important  distinction  which  should 
be  established.  This  is,  that  lesions,  even  extensive  and 
deep,  which  remain  limited  to  the  gray  ganglia  (caudated 
and  lenticular  ganglia),  produce,  as  a  general  rule,  symptoms 
relatively  slight  and  transient,  while  lesions  comparatively 


SECONDARY   DEGENERATION.  1 1/ 

slight,  which  involve  the  white  tract  (internal  capsule),  give 
rise  to  a  motor  hemiplegia,  not  only  very  decided,  but  also 
of  long  duration  and  often  incurable  (Fig.  34). 

Let  us  try  and  ascertain  the  reason  of  these  differences. 
First,  concerning  the  intensity  of  the  paralytic  symptoms  in 
cases  of  lesions  of  the  internal  capsule  compared  to  that  mild 
degree  in  cases  of  lesions  limited  to  the  gray  ganglia  ;  then 
we  will  examine  the  transitory  character  of  hemiplegia  in  the 
last  kind  of  cases  as  contrasted  with  the  permanence  of  the 
same  symptom  which  almost  invariably  results  from  lesions 
of  the  internal  capsule. 

I.  Concerning  the  first  point,  I  will  remind  you  again  of 
the  anatomical  construction  of  the  internal  capsule.  That 
tract  embraces  :  1st.  The  direct  peduncular  fibres — that  is, 
those  originating  beneath  the  gray  cortex,  and  which  enter 
the  inferior  portion  of  the  crura  cerebri  without  having  entered 
into  relation  with  the  lenticular  or  caudated  gray  ganglia. 
2d.  The  indirect  peduncular  fibres,  which,  on  the  contrary, 
originate  in  the  lenticular  or  caudated  ganglia,  and  have  no 
connection  with  the  gray  cortex.  For  the  moment  we  will 
leave  unnoticed  those  fasciculi  of  fibres  which  extend  from  the 
cortical  substance  to  the  gray  ganglia  of  the  central  mass. 

We  will  suppose  that  the  various  peduncular  fibres,  direct 
and  indirect,  are  centrifugal,  and  that  they  transmit  to  the 
periphery  the  motor  influence  developed,  it  may  be,  in  the 
gray  cortex  of  the  brain,  or  in  the  lenticular  and  caudated 
gray  ganglia. 

With  this  hypothesis  it  is  easy  to  comprehend  that  a  small 
lesion  of  the  internal  capsule,  especially  near  its  inferior  part, 
in  the  vicinity  of  the  foot  of  the  cerebral  peduncle,  where  all 
the  fibres  are  reassembled  in  a  narrow  space,  would,  at  one 
blow,  suppress  the  influence  of  the  gray  cortex  and  that  of 
the  two  gray  ganglia  ;  while,  on  the  contrary,  a  lesion  limited 
to  the  lenticular  ganglion  would  leave  free  the  action  of  the 
caudated  ganglion  and  that  of  the  gray  cortex.  The  effects 
of  various  combinations  of  this  sort  which  might  happen  can 
easily  be  imagined  ;  lesion  of  the  caudated  ganglion,  of  cer- 


Il8  DISEASES   OF   THE   BRAIN. 

tain  regions  of  the  gray  cortex,  of  the  two  gray  ganglia,  with 
or  without  the  participation  of  the  peduncular  fibres  of  the 
internal  capsule,  etc. 

I  attach  no  more  importance  to  this  theoretical  view  than 
is  permissible.  It  adapts  itself  well  to  the  facts  obtained  by 
clinical  observation  upon  man,  and  I  will  add  also  that  it  is 
in  no  part  contradicted  (you  may  judge  for  yourselves)  by 
experiments  made  with  animals. 

For  a  long  time  it  has  been  known  l  that  with  the  majority 
of  animals  motor  disturbances  produced  by  the  methodic  de- 
struction of  various  parts  of  the  encephalon,  particularly  of 
the  brain,  differ  considerably  in  a  general  way  from  similar 
pathological  lesions  of  corresponding  parts  in  man. 

In  the  interpretation  of  these  experimental  facts,  and  in 
their  application  to  human  pathology,  there  should  be  taken 
into  account,  among  other  things,  the  greater  or  less  inferior- 
ity of  the  species  of  animals  and  the  more  or  less  advanced 
age.  Thus,  the  entire  ablation  of  a  cerebral  hemisphere  of  a 
pigeon  (and  still  more  marked,  of  course,  with  a  reptile) 
would  produce  no  trouble  which  could  be  compared  to  hemi- 
plegia.  It  is  nearly  the  same  with  the  rabbit.  A  feebleness 
slightly  noticeable  in  the  limbs  of  one  side  of  the  body  is  the 
only  consequence  of  such  a  lesion  in  the  rabbit.  Standing 
and  jumping  are  still  possible,  even  though  the  entire  brain 
has  been  destroyed,  provided  always  that  the  protuberance 
remains  intact.2  With  the  dog,  the  results  become  notably 
different.  From  the  last  experiments  made  in  the  laboratory 
of  Vulpian,  by  Carville  and  Duret,  the  results  of  methodic 
ablation  of  the  various  parts  of  the  dog's  brain  greatly  resem- 
ble those  observed  in  cases  of  corresponding  lesions  of  the 
cerebral  hemisphere  in  man. 

If  the  experiments  were  made  upon  the  monkey,  it  is  prob- 
able that  the  resemblance  would  be  still  more  manifest  and 
complete. 

Here  is  a  brief  expose  of  the  principal  results  obtained  by 

1  See  upon  this  subject  Longet. — Trait e   de  physiologic,  t._III.,   p.  431,    and 
Vulpian. — Le9ons  sur  la  physiologic  generate,  etc.,  p.  676. 

2  Vulpian,  Longet. 


SECONDARY   DEGENERATION. 


119 


lenticular 
Section  of  ant.  portion^    j 
of  internal  capsule  j 

Caudatedniidjei 
*,  of  .corpora  'strata. 

•     t 


the  experiments  of  Carville  and  Duret :  1st.  In  the  dog,  ab- 
lation of  the  gray  substance  of  the  central  cortex  of  those 
regions  called  motor  centres  produced  a  temporary  weakness 
(paresis)  of  the  limbs  upon 
the  opposite  side.  2d.  The 
extirpation  of  the  caudated 
ganglion  produced  an  anal- 
ogous but  more  marked 
paresis.  Nothing  can  at 
present  be  said  of  the  len- 
ticular ganglion,  the  ablation 
of  which,  owing  to  its  topo- 
graphical position,  could  not 
be  effected ; l  3d.  If,  on  the 
contrary,  the  lesion  be  made 
upon  the  inferior  part  of  the 
internal  capsule,  it  produces 
in  both  fore  and  hind  limbs 
of  the  opposite  side,  not 
only  a  simple  paresis,  but 
a  well-marked  motor  paraly- 
sis which  resembles  the  hemiplegia  in  man  resulting  from  le- 
sions of  the  same  parts  (Fig.  35).  Held  suspended  by  the 
skin  of  the  back,  the  animal  thus  operated  on  could  still  stand 
on  the  sound  limbs,  but  the  affected  ones  hung  flaccid,  inert^ 
and  no  longer  capable  of  any  movement  except  that  which  was 
purely  reflex. 

In  short,  you  see  from  these  interesting  researches,  which 
are  worthy  of  multiplication,  that  the  contradiction  long  since 
noticed  between  animals  and  man,  relative  to  the  influence  of 
various  parts  of  the  hemisphere  of  the  brain  upon  movement  of 
the  opposite  limbs — that  contradiction,  I  say,  seems  no  longer 
to  exist  when  the  specimen  for  the  comparison  is  relatively  high 
in  the  animal  scale.  (Fig.  36.) 

Perhaps  it  is  not  here  out  of  the  way  to  recall  that  even  in 

1  In  this  respect  it  is  difficult  to  utilize  the  experiments  of  Nothnagel  with  caus- 
tic injections.  These  injections  must  almost  necessarily  produce  phenomena  of 
excitation,  which  assuredly  introduce  a  complication. 


InLcapsule,1  /''    j    \  !Int.  capsule, 
Chiasma  of  optic  nerves  * 

FIG.  35. — Transverse   section   of  adog'3 
brain,  five  millimetres  anterior  to  the  opti 
chiasma.     (Operation,  of  Veyssttre.} 


I2O 


DISEASES   OF  THE  BRAIN. 


the  dog — the  result  of  experiments  by  both  Carville  and 
Duret  and  Veyssiere — lesions  of  the  posterior  part  of  the  inter- 
nal capsule  produced  crossed  hemianaesthesia  the  same  as 
with  man. 


II.   I  think  the  previous  considerations  may  render  plain 
the  reason  why  hemiplegias  resulting  from  destructive  lesions 

Caudat^d  nuclei 

InV.  capsule,  ppstportion. 


HornsV--'-" 
of-Ammon.  • 

FIG.  36. — Transverse  section  of  a  dog's  brain  on  a  plane  with  the  tubercula  mammil- 
laria.— (Carville  and  Duret. ) 

confined  to  the  substance  of  the  gray  ganglia  are  as  a  rule 
temporary,  while  those  resulting  from  lesions  in  the  substance 
of  the  internal  capsule  are,  on  the  contrary,  of  longer  dura- 
tion, and  often  even  absolutely  incurable. 

Through  the  hypothesis  proposed,  it  can  easily  be  under- 
stood how  the  lenticular  and  caudated  ganglia  and  the  regions 
called  the  motor  centres  in  the  gray  cortex  of  the  hemispheres 
could  mutually  supplement  each  other  in  their  functions,  so 
long  as  the  conducting  fasciculi  which  form  the  capsule  have 
preserved  their  integrity,  and  could  continue  to  maintain  the 
relations  of  any  one  of  the  gray  centres  in  question  with  the 
peripheric  parts  ;  whereas  this  could  not  take  place  if  the 
continuity  of  these  fasciculi  had  been  decidedly  interrupted. 

I  will  add  that  in  all  probability  this  supplementing  may  be 
established  not  only  between  the  various  gray  ganglia,  but 
also  between  the  various  parts  of  the  same  ganglion.  It  is 


SECONDARY  DEGENERATION.  121 

demonstrated,  at  least  as  concerns  the  caudated  ganglion  of 
the  corpus  striatum,  that  partially  destructive  lesions  affecting 
the  most  diverse  regions  of  the  ganglion  are  uniformly  ex- 
pressed by  a  more  or  less  marked  and  transitory,  but  total 
hemiplegia  ;  that  is,  affecting  at  the  same  time  both  the  face 
and  the  limbs.  In  this  respect  there  can  be  distinguished  no 
difference  between  the  head,  the  tail,  or  the  middle  part  of 
the  caudated  ganglion.  It  would  thus  seem  that  H.  Jackson 
was  correct  in  remarking  that  each  parcel  of  the  striated  body 
represented  in  miniature  the  entire  body.  Moreover,  experi- 
mentation gives  results  in  conformity  with  those  furnished  by 
clinical  observation,  in  showing  that  partial  excitation  of  the 
caudated  ganglion,  however  effected,  always  produces  move- 
ments of  the  entire  opposite  side  of  the  body,  and  never  dis- 
associated movements  ;  localized,  for  example,  in  one  limb,  or 
in  a  portion  of  a  limb.1 

In  case  of  a  destructive  lesion  of  the  internal  capsule,  a 
slow  regeneration  of  the  nerve-elements  may,  on  the  contrary, 
permit  the  gradual  re-establishment  of  the  functions.  Now, 
that  labor  of  restitution,  if  it  is  really  sometimes  accomplished, 
most  certainly  is  not  always  so  ;  it  occurs  only  as  an  excep- 
tion. It  is  placed  beyond  doubt,  indeed,  by  very  numerous 
observations,  that  those  lesions  which  to  a  certain  extent  de- 
stroy the  motor  fibres  of  the  internal  capsule,  have,  as  an 
almost  necessary  consequence,  the  production  of  a  fascicular 
lesion  which,  commencing  immediately  below  the  site  of  the 
lesion,  can  be  traced  in  the  corresponding  side  to  the  foot  of 
the  peduncle,  along  the  protuberance,  and  the  anterior  pyr- 
amid to  the  level  of  the  bulbular  decussation,  and  beneath 
this  into  the  spinal  cord,  on  the  side  opposite  to  that  of  the 
lesion,  through  the  entire  length  of  the  lateral  fasciculus  down 
to  the  lumbar  enlargement. 

III.  I  think  some  explanations  concerning  the  anatomy 
and  pathological  physiology  of  secondary  degenerative  or  de- 
scending scleroses,  as  they  still  may  be  called,  will  not  here 

1  Experiences  of  Ferrier,  Carville  and  Duret. 


122  DISEASES   OF  THE   BRAIN. 

be  amiss.  They  are  incontestably  one  of  the  principal  causes 
of  the  persistence  of  motor  impotency  in  the  cases  under  con- 
sideration. In  my  opinion,  we  must  also  join  to  them  the 
major  part  of  permanent  contractions,  called  late  contractions 
(tardive^  which  in  these  cases  sooner  or  later  take  possession 
of  the  paralyzed  limbs,  and  in  a  general  way  play  a  predom- 
inant role  in  the  prognosis  of  cerebral  hemorrhage. 

1st.  Let  us  first  pause  in  face  of  a  fact  which  really  rules 
the  question  :  cerebral  lesions  (en  foyer),  considered  as  re- 
spects their  location,  are  not  all  equally  able  to  produce  con- 
secutive sclerosis. 

Thus,  among  these  lesions,  some  are  never  followed  by 
descending  sclerosis,  while  others  almost  surely  are.  To  this 
last  kind  belong  destructive  lesions,  however  slight,  which, 
according  to  the  important  observation  of  L.  Turck,  involve 
the  fasciculi  of  the  internal  capsule  in  their  course  between  the 
lenticular  and  caudated  ganglia,  that  is,  along  the  anterior 
two-thirds  of  the  capsule.  On  the  contrary,  those  lesions  con- 
fined to  the  substance  of  the  gray  cerebral  masses,  namely, 
the  lenticulated  and  caudated  ganglia  and  the  thalami  optici, 
produce  no  consecutive  sclerosis. 

That  remarkable  fact  was  thoroughly  brought  to  light  by 
L.  Tiirck  2  in  1851.  Vulpian  and  I  have  both  recognized 
its  entire  exactitude  in -the  researches  which  we  have  made 
together  at  Salpetriere  from  1861  to  i866.3  The  important 
works  of  Bouchard  have  equally  confirmed  it.4  There  are  also 
a  certain  number  of  other  facts,  furnished  by  L.  Tiirck,  not  less 
interesting,  and  of  which  the  following  is  the  gist : 

1  We  are  indebted,  as  is  known,  to  Dr.  Todd  for  having  established  a  distinc- 
tion between  early  and  late  (precoce  et  tar  dive)  contraction  in  the  limbs  of  an 
apoplectic.  The  first  appears  at  the  commencement  and  is  nearly  always  transitory ; 
the  other  does  not  appear  before  the  fourteenth  to  the  thirtieth  day  after  the  attack, 
is  situated  always  in  the  limbs  of  the  side  opposite  to  the  lesion,  and  in  the 
majority  of  cases  is  permanent. 

3  L.  /Tiirck. — Ueber  secundare   Erkrankung  einzelner  Riickenmarkstrange  und 
ihrer  Forsetzungen  zum  Gehirne.     Sitzungsber.  der  mathnatur.  Classe  d.  K.  Ak., 
1851.     Idem.,  XI.  Bd.,  1853. 

s  A.  Vulpian. — Physiologic  du  systeme  nerveux,  Paris,  1866. 

4  Ch.  Bouchard.—  Des  degenerations  secondaires  de  la  molle  epiniere.    In  Arch, 
gen.  de  medecine,  1866. 


SECONDARY   DEGENERATION. 


123 


2<d.  Lesions  situated  outside  of  the  central  masses,  in  the 
centrum  ovale  of  Vieussens,  produce  descending  sclerosis, 
provided  they  are  not  too  far  removed  from  the  foot  of  the 
radiating  fibres  (couronne  rayonnante). 

3d.  Lesions  of  the  gray  cortical  substance  of  the  hemi- 
spheres, when  they  are  very  superficial,  such,  for  example,  as 
those  which  habitually  accompany  meningitis,  do  not  produce 
descending  sclerosis. 


'Center  of 
Softening: 

FIG.  37. — Cortical  ischaemic  softening  without  involving  the  central  masses. 

4th.  On  the  contrary,  cortical  lesions  which  are  both 
extended  and  profound,  that  is,  involving  both  the  gray  sub- 
stance and  the  subjacent  medullary  substance,  as  seen  in 
cases  of  ischaemic  softening  resulting,  for  example,  from  the 
obliteration  of  a  voluminous  branch  of  the  Sylvian  artery 
(see  Fig.  37) — these  lesions,  I  say,  even  when  there  is  no  par- 
ticipation of  the  central  masses,  produce  in  certain  cases  con- 
secutive sclerosis  as  marked  as  that  which  depends  upon  a 
lesion  of  the  anterior  region  of  the  internal  capsule. 

Among  these  conditions  there  is  one  especially  relating  to 
the  location  of  cortical  lesions,  which  should  be  made  partic- 
ularly clear.  We  have  observed  that  superficial  softenings 
(yellow  patches)  occupying  either  the  occipital  lobe,  the  pos- 


124 


DISEASES   OF  THE  BRAIN. 


terior  parts  of  the  temporal  or  sphenoidal  lobe,  or  the  ante- 
rior regions  of  the  frontal  lobe,  are  not  succeeded  by  consec- 
utive fascicular  sclerosis,  while  on  the  other  hand  these  scle- 
roses, as  a  rule,  follow  lesions  of  the  two  ascending  convolu- 
tions (ascending  parietal  and  ascending  frontal),  and  the  con- 
tiguous parts  of  the  parietal  and  frontal  lobes  (Fig.  38).  Fur- 
ther on  I  will  return  more  especially  to  this  point,  which  I 
now  merely  mention. 


FIG.  38. — Human  brain,  left  side  ;  destruction  of  the  ascending  parietal  convolu- 
tion and  a  great  part  of  the  ascending  frontal  convolution. 

5th.  In  brief,  the  locality  and  extent  of  the  lesion  seem 
here  to  be  the  two  fundamental  conditions  ;  the  nature  of  the 
lesion  seems  to  have  no  marked  influence.  The  required 
locality  and  extent  being  given,  descending  sclerosis  should 
follow,  provided  the  lesion  is  a  destructive  one,  that  is,  one 
capable  of  interrupting  the  course  of  the  medullary  fibres. 
Centres  of  hemorrhage  or  softening,  and  simple  or  syphilitic 
encephalitis,  have  in  this  respect  much  the  same  rank.  It  is 
not  the  same  with  certain  tumors  which,  through  a  long  period 
of  evolution,  only  crowd  back  or  to  one  side  the  medul- 
lary elements  without  interrupting  their  continuity.  This  is 
the  reason  why  they  may  exist,  even  in  the  regions  above 
specified,  unaccompanied  by  consecutive  fascicular  scle- 
rosis. 


SECONDARY   DEGENERATION.  125 

IV.  As  for  the  anatomy  of  fascicular  sclerosis,  I  refer  for 
details  to  the  important  memoire  published  by  Bouchard.  I 
will  only  remind  you  of  some  facts  to  which  our  present  stud- 
ies give  a  particular  interest. 

1st.  I  will  commence  by  recalling  that  sclerosis  following  a 
lesion  (en  foyer)  in  the  cerebral  hemispheres  always  occupies 
one-half  of  the  lateral  fasciculi.  It  is  more  or  less  marked  and 
more  or  less  extensive  according  to  the  size  of  the  fasciculus  ; 
but  always  extends  down  to  the  inferior  end  of  the  lumbar  en- 
largement, never  stops  by  the  way.  They  are  always  descend- 
ing, in  the  sense  that,  taking  origin  on  a  level  with  the  point 
of  lesion,  they  never  extend  except  below  that  point ;  they 
are  never  found  above  it,  towards  the  gray  cortex.  The 
atrophy  of  one  or  several  of  the  convolutions,  or  even  of  the 
entire  hemisphere,  such  as  is  seen  when  a  central  lesion  (en 
foyer)  is  developed  in  very  young  subjects,  is  not  necessarily 
the  result  of  a  sclerosis.  That  arises  from  an  arrest  of  de- 
velopment which  may  be  compared  to  atrophy,  which,  under 
like  circumstances,  is  to  be  seen  in  the  limbs  upon  the  side 
of  the  body  affected  by  hemiplegia  (infantile  spasmodic  hemi- 
plegia). 

2d.  Microscopic  examination  alone,  in  cases  which  have 
existed  for  some  time  and  are  rather  marked,  can  recognize 
some  of  the  most  prominent  characters  of  the  alteration.  Let 
us  suppose  a  yellow  patch,  interrupting  in  the  left  hemisphere 
the  course  of  the  fibres  of  the  internal  capsule  in  its  middle 
third.  In  such  a  case  the  foot  of  the  crus  cerebri  of  the  left 
side  will  appear  flatter  and  narrower  than  that  of  the  opposite 
side.  There  will  also  be  seen  a  grayish  band  situated  upon 
the  middle  part  of  the  peduncle,1  which  upon  an  antero-pos- 
terior  section  does  not  extend  beyond  the  gray  layer  of  Soem- 
mering.  The  gray  color  disappears  at  the  level  of  the  protu- 
berance ;  it  is  found  again  below,  in  the  bulb,  where  it  occu- 
pies the  entire  extent  of  the  anterior  pyramid  on  the  side 
corresponding  to  the  cerebral  lesion  ;  the  affected  pyramid  is 

1  The  situation  occupied  by  that  band  varies  according  to  the  location  of  the 
central  lesion ;  it  is  nearer  the  internal  border  of  the  foot  of  the  peduncle  in  pro- 
portion as  the  lesion  of  the  capsule  is  situated  anteriorly. 


126  DISEASES   OF  THE   BRAIN. 

narrowed  and  flattened ;  lower  down,  the  teeth  of  the  bulbu- 
lar  decussation  show  more  distinctly  than  in  the  normal  con- 
dition by  reason  of  the  contrast  which  exists  between  the 
sound  and  diseased  sides.  Below  the  decussation  it  is  in  the 
opposite  side  of  the  spinal  cord  (opposite  to  the  affected 
hemisphere),  in  the  lateral  fasciculus,  that  the  sclerosis  should 
be  sought  for ;  the  alteration  is  in  the  form  of  a  triangular 
space,  of  gray  color,  situated  immediately  external  and  ante- 
rior to  the  corresponding  posterior  gray  cornu,  the  area  of 
which  lessens  in  proportion  as  the  sections  are  made  lower 
down  on  the  cord. 

3d.  Microscopic  studies,  made  upon  sections  properly  hard- 
ened and  prepared,  greatly  contribute  to  our  knowledge. 
In  the  first  place,  they  furnish  the  means  for  locating  more 
exactly  the  topography  of  the  lesion,  and  to  make  known,  in 
the  spinal  cord,  for  example,  the  precise  limitation  of  the  area 
in  the  lateral  fasciculus.  The  other  white  fasciculi  and  the  gray 
cornua  remain  entirely  unchanged.  It  is  to  be  noticed,  at  the 
same  time,  that  the  roots  of  the  nerves,  anterior  and  poste- 
rior, as  well  as  the  meninges,  exhibit  no  trace  of  alteration. 

Lastly,  the  microscope  makes  known  also  the  nature  of  the 
morbid  process,  and  furnishes  proof  of  a  gray  induration — a 
sclerosis  which  differs  in  no  essential  particular  from  that 
observed  in  cases  of  primitive  fascicular  sclerosis.1 

4th.  Here  is  the  place  to  call  attention  to  the  analogies 
which  exist  in  an  anatomico-pathological  point  of  view  be- 
tween consecutive  fascicular  sclerosis,  of  cerebral  origin,  and 
those  primitive  and  symmetrical  fascicular  scleroses  of  the  lat- 
eral fasciculi  which  I  last  year  described  in  connection  with 
spinal  muscular  atrophy  (amyotrophies  spinales}. 

These  analogies  are  considerable,  since  the  same  alteration 
(gray  induration)  is  in  both  cases  located  in  the  same  tissue. 
But  there  are  also  variations  worthy  of  notice  ;  thus,  in  prim- 
itive sclerosis  the  fascicular  lesions  are  necessarily  double,  that 

1  Those  cases  where  the  extension  of  the  lesion  exceeds  its  habitual  limits,  the 
invasion,  for  example,  of  the  anterior  gray  cornua,  which  will  be  considered  farther 
on,  are  certainly  among  the  most  decisive  arguments  which  can  be  employed  to 
establish  the  irritative  nature  of  the  morbid  process. 


SECONDARY   DEGENERATION. 


127 


is,  they  occupy  the  lateral  fasciculi  of  both  sides  simulta- 
neously, instead  of  one  side  only,  as  is  always  the  case  in  con- 
secutive sclerosis,  when  the  lesion  from  which  it  arises  is  uni- 
lateral. I  will  also  add  that  it  is  very  much  less  extended 
transversely,  and  there  is  reason  to  believe,  therefore,  that 
beyond  the  cerebro-spinal  or  pyramidal  fibres,  which  are  the 
only  ones  affected  in  consecutive  sclerosis,  primitive  sclero- 


FIG.  40. 


FIG.  39. 


FIG.  39.— Transverse  section  of  the  spinal  cord  in  a  case  of  consecutive  lateral  fas- 
cicular sclerosis  ;  from  softening  of  the  optico-striated  bodies  and  the  internal  capsule. 
(Cervical  region.) 

FIG.  40.— Transverse  section  of  the  spinal  cord  in  a  case  of  consecutive  lateral 
fascicular  sclerosis.  (Dorsal  region.) 

sis  invades  also  the  spinal  fibres  of  the  lateral  fasciculus  (com- 
pare Figs.  39,  40,  and  41,  and  Figs.  42,  43,  and  44). 


FIG.  41. 


FIG.  42. 


FIG.  41. — Transverse  section  of  the  spinal  cord  in  a  case  of  consecutive  lateral 
fascicular  sclerosis.  (Lumbar  region.) 

FIG.  42. — Transverse  section  of  the  spinal  cord  in  a  case  of  primitive  lateral 
fascicular  sclerosis.  (Middle  portion  of  cervical  enlargement.) 

Finally,  primitive  sclerosis  has  a  great  tendency  to  extend 
to  the  neighboring  spinal  regions,  to  the  white  fasciculi,  and 


128 


DISEASES   OF   THE   BRAIN. 


especially  the  anterior  cornua  of  the  gray  substance,  which 
is  not  the  rule  in  the  consecutive  form.1 


FIG.  43. 


FIG.  44- 


FIG.  43. — Transverse  section  of  the  spinal  cord  in  a  case  of  primitive  lateral  fas- 
cicular  sclerosis.  (Middle  of  dorsal  region. ) 

FIG.  44-—  Transverse  section  of  the  spinal  cord  in  a  case  of  primitive  lateral 
fascicular  sclerosis.  (Middle  of  lumbar  enlargement.) 

1  Here  are  some  more  precise  details  relative  to  the  anatomical  differences 
existing  between  consecutive  lateral  sclerosis  and  primitive  lateral  sclerosis,  amyo- 
trophic.  They  are  examinations  made  upon  hardened  transverse  sections,  where, 
even  in  the  bulb,  secondary  sclerosis  has  involved  nearly  all  the  fibres  of  the  ante- 
rior pyramid,  and  in  the  spinal  cord  the  lesion  occupies  only  a  comparatively  nar- 
row space  in  the  lateral  fasciculus.  Upon  a  transverse  section  made  at  the  cervi- 
cal enlargement,  the  lesion  is  seen  as  a  triangle  with  very  clearly  defined  borders, 
the  apex  of  which  is  directed  inward  toward  the  angle  which  separates  the  ante- 
rior from  the  posterior  gray  cornua,  the  base  a  little  rounded,  does  not  extend  to 
the  circumference  of  the  cord,  neither  does  it  involve  the  antero-external  border  of 
the  posterior  cornu  (Fig.  39).  In  the  dorsal  region  the  sclerotic  portion  pro- 
gressively diminishes  in  diameter  and  tends  to  resume  an  oval  form  (Fig.  40). 
Finally,  in  the  lumbar  enlargement  (Fig.  41),  it  resumes  as  in  the  cervical  region,  a 
sort  of  triangle,  but  in  this  locality  the  base  of  the  triangle  is  quite  superficial,  next 
to  the  pia  mater. 

In  primitive  lateral  sclerosis,  the  sclerotic  zone  occupies  in  a  general  way  the 
same  region  as  does  consecutive  sclerosis,  but  its  area  is  much  greater.  Thus, 
anteriorly,  the  lesion  tends  to  invade  the  anterior  radiating  zones,  and  internally 
it  extends  so  as  to  come  in  contact  with  the  nerve-fibres  (perhaps  sensitive)  which 
constitute  the  profound  part  of  the  lateral  fasciculi  (see  Figs.  42,  43,  44).  It  must 
be  added  that  here  the  borders  of  the  lesions  become  ill-defined.  In  some  cases 
they  seem  to  be  confounded  with  the  gray  substance.  It  is  known  that  the  gray 
substance  is  regularly  invaded  by  sclerotic  alterations  in  cases  of  lateral  amyotro- 
phic  sclerosis,  whereas  it  is  very  exceptional  in  consecutive  sclerosis  from  cerebral 
cause. 

From  the  preceding  considerations  there  is  reason  to  think  that  consecutive 
sclerosis  affects  only  one  part  of  the  nerve-fibres  which  compose  the  lateral  fas- 
ciculi, namely,  the  cerebro-spinal  fibres  ;  whereas,  in  primitive  sclerosis,  it  invades 


SECONDARY  DEGENERATION.  129 

There  is,  however,  a  chapter  of  exceptions  which  in  this 
connection  is  particularly  interesting. 

IV.  The  facts  gathered  in  the  course  of  the  preceding 
expose  enable  us  to  justify  the  proposition  with  which  this 
chapter  commenced.  We  have  established  in  an  anatomical 
point  of  view  that  there  exists  a  very  considerable  analogy 
between  primitive  and  consecutive  forms  of  lateral  fascicular 
sclerosis.  That  assimilation  can  be  followed  upon  the  clini- 
cal field.  It  is  known,  indeed,  that  motor  loss,  contraction  of 
the  limbs,  at  first  transient,  then  permanent,  with  sponta- 
neous or  provoked  trepidation,  etc.,  provide  a  symptomatic 
group  which  reveals  during  life  the  existence  of  primitive 
fascicular  spinal  sclerosis,  that  is,  independent  of  any  cerebral 
lesion.  Now  all  the  essential  characters  of  these  symptoms 
are  reproduced  in  sclerosis  arising  from  a  lesion  in  the  brain, 
the  clinical  picture,  in  fact,  of  common  permanent  hemiplegia. 
It  may  be  said,  then,  that  there  exists  a  relation  between  the 
phenomenon  of  "  permanent  contraction  "  and  "  lateral  sclero- 
sis," the  physiological  reason  of  which  at  present  completely 
eludes  us,  but  the  reality  of  which  is  nevertheless  established 
by  a  great  number  of  observations.1 

In  my  opinion,  it  is  not  the  retraction  of  the  cerebral  cica- 
trix,  as  Todd  would  hold,  nor  yet  encephalitis  supervening 
from  proximity  to  the  lesion,  as  very  many  authors  at  present 
maintain,  which  can  explain  the  apparition  of  those  contrac- 
tions in  hemiplegias  called  tardy  (tardive)  ;  on  the  contrary, 
it  is  more  reasonable  to  attribute  it  to  a  chronic  myelitis  in 
the  lateral  fasciculus  resulting  from  the  cerebral  lesion.  I  will 
avoid  discussion,  and  once  more  refer  you  to  the  work  already 
cited  of  Bouchard,  in  which  will  be  found  all  the  proofs  that 
can  be  adduced  in  favor  of  my  opinion. 

Consecutive    sclerosis   resulting   from    cerebral   lesion    ac- 

the  entire  lateral  system,  including  not  only  the  cerebro-spinal  and  pyramidal 
fibres,  but  also  those  fibres  which  both  commence  and  terminate  in  the  spinal 
cord — those  fibres  properly  called  spinal  fibres. 

1  Permanent  contraction  of  the  limbs,  as  is  seen  in  other  complaints,  such  ds  hys- 
teria, may  exist  without  lateral  spinal  sclerosis ;  but  when  that  lesion  exists,  per- 
manent contraction  is  an  habitual  symptom, 

9 


130  DISEASES   OF  THE   BRAIN. 

quires,  after  a  given  time,  a  kind  of  independent  existence, 
automatic  ;  this  is  evinced  by  special  symptoms.  By  reason 
of  this  autonomy  the  lesion  may  happen  to  extend  beyond 
the  limits  habitually  assigned  to  it  in  the  lateral  fasciculus,  and 
invade  the  adjacent  parts  of  the  spinal  cord,  the  substance  of 
the  gray  cornua,  for  example  ;  in  such  cases  it  is  comprehen- 
sible that  important  modifications  may  occur  in  the  symp- 
tomatic tableau  ;  thus,  the  muscles  of  the  paralyzed  limbs, 
which  in  permanent  hemiplegia  ordinarily  preserve  their  nor- 
mal texture  for  a  long  time,  and  but  slowly  emaciate,  are 
subject,  in  certain  cases,  to  a  degenerative  atrophy,  more  or 
less  rapid,  at  the  same  time  that  the  rigidity  of  the  contrac- 
tion gives  way  to  renewed  flaccidity.  In  several  examples 
of  this  kind,  Pierret  and  I  have  demonstrated,  in  addition  to 
the  classic  lateral  sclerosis,  a  lesion  of  the  anterior  gray  cornu 
of  the  same  side,  including  the  destruction  of  the  large  nerve- 
cells  of  that  region.  The  invasion  of  the  posterior  gray  cor- 
nu might  in  like  manner  explain  the  appearance  of  certain 
partial  anaesthesia  in  common  hemiplegia.  Lastly,  the  exten- 
sion of  the  initiative  process,  whether  along  the  whole  course 
of  the  lateral  fasciculus  of  the  corresponding  side,  or  be  it  of 
the  lateral  fasciculus  of  the  opposite  side,  would  doubtless  ex- 
plain the  fact  that,  contrary  to  common  observation,  the  con- 
traction of  the  lower  limb  is  at  some  one  period  considerably 
greater,  or  sometimes  extends  to  the  opposite  limb.1 

V.  To  the  present  I  have  only  occupied  myself  with  fas- 
cicular  sclerosis  arising  from  lesion  of  the  central  cerebral 
masses.  I  now  wish  to  give  a  moment  to  those  produced  by 
lesions  of  the  cortex.  So  far  as  concerns  the  affection  of  the 
spine  or  the  bulb,  lateral  sclerosis,  from  lesions  of  the  cen- 
tral masses,  in  no  way  differs  from  that  following  lesions  of  the 
cortex.  The  special  conditions  of  development  constitute  all 
the  difference,  and  this  calls  for  new  details. 

You  remember  how  you  have  been  led  to  admit,  on  the 
grounds  of  a  very  probable  hypothesis,  the  existence  of  di- 

1  In  this  connection  see  Bastian — Paralysis  from  Brain  Diseases,  etc.,  p.  141. 
London,  1875. 


SECONDARY   DEGENERATION.  131 

rect  peduncular  fibres — that  is,  those  which,  after  leaving  the 
foot  of  the  peduncle,  traverse  the  internal  capsule  without 
entering  the  gray  ganglia  of  the  central  masses,  and  conse- 
quently do  not  stop  until  they  reach  the  gray  cortical  sub- 
stance ;  besides  the  arguments  already  employed,  some  facts 
of  experimentation  can  be  cited  in  favor  of  the  existence  of 
such  fibres,  even  with  animals  of  low  scale,  the  rabbit  for  ex- 
ample. Thus  in  the  experiments  already  noticed  of  Gudden,1 
made  upon  very  young  animals,  it  is  seen  that  eight  months 
after  the  removal  of  the  anterior  part  of  a  hemisphere,  the 
central  masses,  thalami  optici,  and  corpora  striata  being  un- 
touched, the  internal  capsule  of  the  corresponding  side  atro- 
phies in  a  remarkable  manner.  It  is  clear  that  such  atrophy 
would  not  occur  if  the  internal  capsule,  as  some  anatomists 
hold,  were  exclusively  composed  of  indirect  peduncular  fibres, 
—that  is,  of  fibres  terminating  in  the  substance  of  the  central 
gray  ganglia. 

Chance  brought  to  the  notice  of  Carville  and  Duret2  a 
lesion  in  a  dog  which  had  destroyed  all  the  white  substance 
of  the  frontal  portion  of  a  lobe  without  directly  affecting  the 
central  gray  ganglia  or  the  internal  capsule.  In  this  case 
there  was  a  very  marked  atrophy  of  the  foot  of  the  peduncle, 
the  protuberance,  and  of  the  pyramidal  bulb  of  the  side"  cor- 
responding to  the  cerebral  lesion. 

The  reality  of  these  direct  peduncular  fibres  in  man  seems 
in  its  turn  to  be  proven  by  the  production  of  the  secondary 
degenerations  which,  as  we  have  said,  are  a  result  of  exten- 
sive and  deep  lesions  of  the  gray  cortical  substance. 

Do  these  direct  peduncular  fibres,  after  their  disappearance 
in  the  diverging  fibres,  spread  indifferently  to  all  parts  of  the 
hemisphere,  or  are  they  assigned  to  special  departments  of 
the  gray  cortex  ?  The  facts  which  I  have  collected  towards 
the  study  of  that  question  plead  in  favor  of  the  last  hypothe- 
sis. These  observations,  collected  for  me  at  the  Hospital  of 
Saltpetriere  during  the  last  fifteen  years,  relate  to  cases  of 

1  Archiv  fur  Psychiatric,  Bd.    II.,   1870,  pi.  VIII. 
3  Archives  de  physiologic,  1875. 


132 


DISEASES   OF   THE   BRAIN. 


long-standing  ischaemic  softening.1  The  lesions  in  these  cases 
appeared  as  yellow  patches  of  variable  size,  extending  more 
or  less  deeply  into  the  subjacent  white  substance  and  occu- 
pying the  most  diverse  regions  of  the  surface  of  the  hemi- 
spheres. In  all  the  cases  it  is  expressly  mentioned  that  the 
softenings  had  left  the  central  masses,  thalami  optici,  cau- 
dated  and  lenticular  ganglia,  and  internal  capsule,  entirely 
untouched.  My  observations  may  be  divided  into  two 
groups. 


FIG.  45. — Human  brain,  left  side ;  destruction  of  the  ascending  parietal  convolu- 
tion and  a  great  part  of  the  ascending  frontal  convolution. 

The  first  includes  those  cases  where  no  permanent  hemi- 
plegia  existed  during  life,  and  where  autopsy  discovered  no 
consecutive  degeneration.  In  all  these  cases  the  convolu- 
tions fed  by  the  Sylvian  artery,  and  especially  the  ascending 
frontal  and  parietal  convolutions,  had  remained  unharmed. 
The  yellow  patch  occupied  one  of  the  following  regions, 
namely,  some  part  of  the  sphenoidal  lobes,  the  quadrilateral 
lobule,  the  cuneus,  one  or  both  of  the  occipital  lobes,  and  a 
region  ranging  over  the  anterior  two-thirds  of  the  frontal 
lobes. 

1  The  most  of  these  observations  are  accompanied  by  designs  made  from  nature  ; 
it  can  be  understood  that  the  place  and  extent  of  the  lesion  are  thus  more  exactly 
located,  and  consequently  the  ordinary  insufficiency  of  description  is  avoided. 


SECONDARY  DEGENERATION.  133 

In  all  cases  of  the  second  group,  there  had  been,  on  the 
contrary,  a  permanent  hemiplegia,  and  the  consecutive  sclero- 
sis was  perfectly  marked.  The  distinguishing  feature  of  these 
cases  was,  that  the  lesion  always  involved  more  or  less  one  or 
the  other  of  the  ascending  frontal  or  parietal  convolutions, 
chiefly  in  their  superior  half,  and  often  both  of  the  convolu- 
tions were  at  the  same  time  affected  ;  besides,  the  regions 
nearest  to  the  frontal  and  parietal  convolutions  generally 
participated.  The  design  which  I  place  before  you  is  a  very 
marked  example  (Fig.  45). 

From  the  preceding,  as  I  before  said,  it  would  seem  that 
secondary  sclerosis,  resulting  from  destructive  lesions  of  the 
cerebral  cortex,  are  subordinate  to  location.  I  will  add,  in 
conclusion,  that  those  portions  of  the  cortex  a  lesion  of 
which  determines  secondary  degenerations  exclusively,  cor- 
respond to  those  parts  which  experimentation  with  the  mon- 
key has  designated  as  the  psycho-motor  centres.  They  are 
the  same  also  where  the  gray  cortical  substance  contains  the 
largest  pyramidal  cells. 

I  have  brought  into  relief  an  important  fact,  which  should 
be  utilized  in  the  study  of  localization  in  the  cerebral  cortex  ; 
a  difficult  study  which  we  will  attempt  in  our  next  lectures. 


TFORNIA  LIBRARY 


14  DAY  USE 

RETURN  TO  DESK  FROM  WHICH  BORROWED 

(iw  r  ' 

lb.!.    '         '': 


This  book  is  due  on  the  last  date  stamped  below,  or 

on  the  date  to  which  renewed. 
Renewed  books  are  subject  to  immediate  recall. 


APR    3,''1 

\ 

MAR  3  n  1961 

REC'D  BIOS 


W22  01-400 


IMMEDIATELY 


LD  21-50m-6,'59 
(A2845slO)476 


General  Library 

University  of  California 

Berkeley 


I 


